Fred heaved a deep sigh.

'Shame. I really fancied finding out what old Snape's been up to.'

'Snape!' said Harry quickly. 'Is he here?'

'Yeah,' said George, carefully closing the door and sitting down on one of the beds; Fred and Ginny followed. 'Giving a report. Top secret.'

'Git,' said Fred idly.

'He's on our side now,' said Hermione reprovingly.

Ron snorted. 'Doesn't stop him being a git. The way he looks at us when he sees us.'

'Bill doesn't like him, either,' said Ginny, as though that settled the matter.

The three of them looked cautiously over the banisters. The gloomy hallway below was packed with witches and wizards, including all of Harrys guard. They were whispering excitedly together. In the very centre of the group Harry saw the dark, greasy-haired head and prominent nose of his least favourite teacher at Hogwarts, Professor Snape. Harry leant further over the banisters. He was very interested in what Snape was doing for the Order of the Phoenix…

They heard the front door open, then close.

'Snape never eats here,' Ron told Harry quietly. Thank God. C'mon.'

'Oh yeah,' said Sirius sarcastically. 'Listening to Snape's reports, having to take all his snide hints that he's out there risking his life while I'm sat on my backside here having a nice comfortable time… asking me how the cleanings going -'

Opposite Harry, Tonks was entertaining Hermione and Ginny by transforming her nose between mouthfuls. Screwing up her eyes each time with the same pained expression she had worn back in Harry's bedroom, her nose swelled to a beak-like protuberance that resembled Snape's, shrank to the size of a button mushroom and then sprouted a great deal of hair from each nostril. Apparently this was a regular mealtime entertainment, because Hermione and Ginny were soon requesting their favourite noses.

Snape might refer to their work as 'cleaning', but in Harrys opinion they were really waging war on the house, which was putting up a very good fight, aided and abetted by Kreacher. The house-elf kept appearing wherever they were congregated, his muttering becoming more and more offensive as he attempted to remove anything he could from the rubbish sacks. Sirius went as far as to threaten him with clothes, but Kreacher fixed him with a watery stare and said, 'Master must do as Master wishes,' before turning away and muttering very loudly, 'but Master will not turn Kreacher away, no, because Kreacher knows what they are up to, oh yes, he is plotting against the Dark Lord, yes, with these Mudbloods and traitors and scum…'

The doorbell rang several times a day, which was the cue for Sirius's mother to start shrieking again, and for Harry and the others to attempt to eavesdrop on the visitor, though they gleaned very little from the brief glimpses and snatches of conversation they were able to sneak before Mrs Weasley recalled them to their tasks. Snape flitted in and out of the house several times more, though to Harry's relief they never came face to face; Harry also caught sight of his Transfiguration teacher Professor McGonagall, looking very odd in a Muggle dress and coat, and she also seemed too busy to linger.

They reached the bottom of the steps and ran along yet another corridor, which bore a great resemblance to the one that led to Snape's dungeon at Hogwarts, with rough stone walls and torches in brackets. The doors they passed here were heavy wooden ones with iron bolts and keyholes.

Divination and double Defence Against the Dark Arts… Binns, Snape, Trelawney and that Umbridge woman all in one day! I wish Fred and George'd hurry up and get those Skiving Snackboxes sorted…'

A fine misty drizzle was falling, so that the people standing in huddles around the edges of the yard looked blurred at the edges. Harry, Ron and Hermione chose a secluded corner under a heavily dripping balcony, turning up the collars of their robes against the chilly September air and talking about what Snape was likely to set them in the first lesson of the year. They had got as far as agreeing that it was likely to be something extremely difficult, just to catch them off guard after a two-month holiday, when someone walked around the corner towards them.

'That's the bell,' said Harry dully, because Ron and Hermione were bickering too loudly to hear it. They did not stop arguing all the way down to Snape's dungeon, which gave Harry plenty of time to reflect that between Neville and Ron he would be lucky ever to have two minutes of conversation with Cho that he could look back on without wanting to leave the country.

And yet, he thought, as they joined the queue lining up outside Snape's classroom door, she had chosen to come and talk to him, hadn't she? She had been Cedric's girlfriend; she could easily have hated Harry for coming out of the Triwizard maze alive when Cedric had died, yet she was talking to him in a perfectly friendly way, not as though she thought him mad, or a liar, or in some horrible way responsible for Cedric's death… yes, she had definitely chosen to come and talk to him, and that made the second time in two days… and at this thought, Harry's spirits rose. Even the ominous sound of Snape's dungeon door creaking open did not puncture the small, hopeful bubble that seemed to have swelled in his chest. He filed into the classroom behind Ron and Hermione and followed them to their usual table at the back, where he sat down between Ron and Hermione and ignored the huffy, irritable noises now issuing from both of them.

'Settle down,' said Snape coldly, shutting the door behind him.

There was no real need for the call to order; the moment the class had heard the door close, quiet had fallen and all fidgeting stopped. Snape's mere presence was usually enough to ensure a class's silence.

'Before we begin today's lesson,' said Snape, sweeping over to his desk and staring around at them all, 'I think it appropriate to remind you that next June you will be sitting an important examination, during which you will prove how much you have learned about the composition and use of magical potions. Moronic though some of this class undoubtedly are, I expect you to scrape an "Acceptable" in your OWL, or suffer my… displeasure.'

His gaze lingered this time on Neville, who gulped.

'After this year, of course, many of you will cease studying with me,' Snape went on. '1 take only the very best into my NEWT Potions class, which means that some of us will certainly be saying goodbye.'

His eyes rested on Harry and his lip curled. Harry glared back, feeling a grim pleasure at the idea that he would be able to give up Potions after fifth year.

'But we have another year to go before that happy moment of farewell,' said Snape softly, 'so, whether or not you are intending to attempt NEWT, I advise all of you to concentrate your efforts upon maintaining the high pass level I have come to expect from my OWL students.

Today we will be mixing a potion that often comes up at Ordinary Wizarding Level: the Draught of Peace, a potion to calm anxiety and soothe agitation. Be warned: if you are too heavy-handed with the ingredients you will put the drinker into a heavy and sometimes irreversible sleep, so you will need to pay close attention to what you are doing.' On Harry's left, Hermione sat up a little straighter, her expression one of utmost attention. The ingredients and method -' Snape flicked his wand '- are on the blackboard -' (they appeared there) '- you will find everything you need -' he flicked his wand again '- in the store cupboard -' (the door of the said cupboard sprang open) '- you have an hour and a half… start.'

Just as Harry, Ron and Hermione had predicted, Snape could hardly have set them a more difficult, fiddly potion. The ingredients had to be added to the cauldron in precisely the right order and quantities; the mixture had to be stirred exactly the right number of times, firstly in clockwise, then in anti-clockwise directions; the heat of the flames on which it was simmering had to be lowered to exactly the right level for a specific number of minutes before the final ingredient was added.

'A light silver vapour should now be rising from your potion,' called Snape, with ten minutes left to go.

Harry, who was sweating profusely, looked desperately around the dungeon. His own cauldron was issuing copious amounts of dark grey steam; Ron's was spitting green sparks. Seamus was feverishly prodding the flames at the base of his cauldron with the tip of his wand, as they seemed to be going out. The surface of Hermione's potion, however, was a shimmering mist of silver vapour, and as Snape swept by he looked down his hooked nose at it without comment, which meant he could find nothing to criticise.

At Harry's cauldron, however, Snape stopped, and looked down at it with a horrible smirk on his face.

'Potter, what is this supposed to be?'

The Slytherins at the front of the class all looked up eagerly; they loved hearing Snape taunt Harry.

The Draught of Peace,' said Harry tensely.

Tell me, Potter,' said Snape softly, 'can you read?'

Draco Malfoy laughed.

'Yes, I can,' said Harry, his fingers clenched tightly around his wand.

'Read the third line of the instructions for me, Potter.'

Harry squinted at the blackboard; it was not easy to make out the instructions through the haze of multi-coloured steam now filling the dungeon.

'"Add powdered moonstone, stir three times counter-clockwise, allow to simmer for seven minutes then add two drops of syrup of hellebore."'

His heart sank. He had not added syrup of hellebore, but had proceeded straight to the fourth line of the instructions after allowing his potion to simmer for seven minutes.

'Did you do everything on the third line, Potter?'

'No,' said Harry very quietly.

'I beg your pardon?'

'No,' said Harry, more loudly. 'I forgot the hellebore.'

'I know you did, Potter, which means that this mess is utterly worthless. Evanesce.'

The contents of Harry's potion vanished; he was left standing foolishly beside an empty cauldron.

Those of you who have managed to read the instructions, fill one flagon with a sample of your potion, label it clearly with your name and bring it up to my desk for testing,' said Snape. 'Homework: twelve inches of parchment on the properties of moonstone and its uses in potion-making, to be handed in on Thursday.'

Neville was now having to gouge out of his cauldron; yet it was he, Harry, who would be receiving zero marks for the day's work. He stuffed his wand back into his bag and slumped down on to his seat, watching everyone else march up to Snape's desk with filled and corked flagons. When at long last the bell rang, Harry was first out of the dungeon and had already started his lunch by the time Ron and Hermione joined him in the Great Hall. The ceiling had turned an even murkier grey during the morning. Rain was lashing the high windows.

That was really unfair,' said Hermione consolingly, sitting down next to Harry and helping herself to shepherd's pie. 'Your potion wasn't nearly as bad as Goyle's; when he put it in his flagon the whole thing shattered and set his robes on fire.'

'Yeah, well,' said Harry, glowering at his plate, 'since when has Snape ever been fair to me?'

Neither of the others answered; all three of them knew that Snape and Harry's mutual enmity had been absolute from the moment Harry had set foot in Hogwarts.

'I did think he might be a bit better this year,' said Hermione in a disappointed voice. 'I mean… you know…' she looked around carefully; there were half a dozen empty seats on either side of them and nobody was passing the table '… now he's in the Order and everything.'

'Poisonous toadstools don't change their spots,' said Ron sagely. 'Anyway I've always thought Dumbledore was cracked to trust Snape. Where's the evidence he ever really stopped working for You-Know-Who?'

'I think Dumbledore's probably got plenty of evidence, even if he doesn't share it with you, Ron,' snapped Hermione.

'Oh, shut up, the pair of you,' said Harry heavily, as Ron opened his mouth to argue back. Hermione and Ron both froze, looking angry and offended. 'Can't you give it a rest?' said Harry. 'You're always having a go at each other, it's driving me mad.' And abandoning his shepherd's pie, he swung his schoolbag back over his shoulder and left them sitting there.

'I'm just passing on the message,' said Ron, talking over him. 'But I reckon she's right. It's not our fault how Seamus and Snape treat you.'

'D'you realise how much homework we've got already? Binns set us a foot-and-a-half-long essay on giant wars, Snape wants a foot on the use of moonstones, and now we've got a month's dream diary from Trelawney! Fred and George weren't wrong about OWL year, were they? That Umbridge woman had better not give us any…"

'Shall we do Snape's stuff first?' said Ron, dipping his quill into his ink. "The properties… of moonstone… and its uses … in potion-making…'" he muttered, writing the words across the top of his parchment as he spoke them. There.' He underlined the title, then looked up expectantly at Hermione.

'They should at least see what they're picking up,' he said firmly. 'Anyway…' he rolled up the parchment on which he had written the title of Snape's essay, 'there's no point trying to finish this now, I can't do it without Hermione, I haven't got a clue what you're supposed to do with moonstones, have you?'

'But on the plus side, no Snape today' said Ron bracingly.

His homework situation, however, was now desperate, and when he returned to the Gryffindor common room he did not, though exhausted, go to bed, but opened his books and began Snape's moonstone essay. It was half past two by the time he had finished it. He knew he had done a poor job, but there was no help for it; unless he had something to give in he would be in detention with Snape next. He then dashed off answers to the questions Professor McGonagall had set them, cobbled together something on the proper handling of Bowtruckles for Professor Grubbly-Plank, and staggered up to bed, where he fell fully clothed on top of the covers and fell asleep immediately.

Harry had never before considered the possibility that there might be another teacher in the world he hated more than Snape, but as he walked back towards Gryffindor Tower he had to admit he had found a strong contender.

But Professor Umbridge was not inspecting their History of Magic lesson, which was just as dull as the previous Monday, nor was she in Snape's dungeon when they arrived for double Potions, where Harry's moonstone essay was handed back to him with a large, spiky black 'D' scrawled in an upper corner.

'I have awarded you the grades you would have received if you presented this work in your OWL,' said Snape with a smirk, as he swept among them, passing back their homework. This should give you a realistic idea of what to expect in the examination.'

Snape reached the front of the class and turned on his heel to face them.

The general standard of this homework was abysmal. Most of you would have failed had this been your examination. I expect to see a great deal more effort for this weeks essay on the various varieties of venom antidotes, or I shall have to start handing out detentions to those dunces who get a "D"'.

He smirked as Malfoy sniggered and said in a carrying whisper, 'Some people got a "D"? Ha!'

Determined not to give Snape an excuse to fail him this lesson, Harry read and reread every line of instructions on the blackboard at least three times before acting on them. His Strengthening Solution was not precisely the clear turquoise shade of Hermione's but it was at least blue rather than pink, like Neville's, and he delivered a flask of it to Snape's desk at the end of the lesson with a feeling of mingled defiance and relief.

'Oh, I dunno…' said Harry desperately, who could not remember dreaming anything at all over the last few days. 'Lets say I dreamed I was… drowning Snape in my cauldron. Yeah, that'll do…'

Ron chortled as he opened his Dream Oracle.

'OK, we've got to add your age to the date you had the dream, the number of letters in the subject… would that be "drowning" or "cauldron" or "Snape"?'

Harry's detentions with Umbridge were finally over (he doubted whether the words now etched into the back of his hand would ever fade entirely); Ron had had four more Quidditch practices and not been shouted at during the last two; and all three of them had managed to Vanish their mice in Transfiguration (Hermione had actually progressed to Vanishing kittens), before the subject was broached again, on a wild, blustery evening at the end of September, when the three of them were sitting in the library, looking up potion ingredients for Snape.

They trudged down the stone steps to the dungeons for Potions, all three of them lost in thought, but as they reached the bottom of the steps they were recalled to themselves by the voice of Draco Malfoy who was standing just outside Snape's classroom door, waving around an official-looking piece of parchment and talking much louder than was necessary so that they could hear every word.

'Not… funny… don't… Mungo's… show… him…'

The dungeon door opened. Snape appeared there. His black eyes swept up the Gryffindor line to the point where Harry and Ron were wrestling with Neville.

'Fighting, Potter, Weasley, Longbottom?' Snape said in his cold, sneering voice. Ten points from Gryffindor. Release Longbottom, Potter, or it will be detention. Inside, all of you.'

Harry, Ron and Hermione took their usual seats at the back of the class, pulled out parchment, quills and their copies of One Thousand Magical Herbs and Fungi. The class around them was whispering about what Neville had just done, but when Snape closed the dungeon door with an echoing bang, everybody immediately fell silent.

'You will notice,' said Snape, in his low, sneering voice, 'that we have a guest with us today.'

He gestured towards the dim corner of the dungeon and Harry saw Professor Umbridge sitting there, clipboard on her knee. He glanced sideways at Ron and Hermione, his eyebrows raised. Snape and Umbridge, the two teachers he hated most. It was hard to decide which one he wanted to triumph over the other.

'We are continuing with our Strengthening Solution today. You will find your mixtures as you left them last lesson; if correctly made they should have matured well over the weekend - instructions -' he waved his wand again '- on the board. Carry on.'

Professor Umbridge spent the first half hour of the lesson making notes in her corner. Harry was very interested in hearing her question Snape; so interested, that he was becoming careless with his potion again.

'Right,' said Harry vaguely, putting down the bottle and continuing to watch the corner. Umbridge had just got to her feet. 'Ha,' he said softly, as she strode between two lines of desks towards Snape, who was bending over Dean Thomas's cauldron.

'Well, the class seem fairly advanced for their level,' she said briskly to Snape's back. Though I would question whether it is advisable to teach them a potion like the Strengthening Solution. I think the Ministry would prefer it if that was removed from the syllabus.'

Snape straightened up slowly and turned to look at her.

'Now… how long have you been teaching at Hogwarts?' she asked, her quill poised over her clipboard.

'Fourteen years,' Snape replied. His expression was unfathomable. Harry, watching him closely, added a few drops to his potion; it hissed menacingly and turned from turquoise to orange.

'You applied first for the Defence Against the Dark Arts post, I believe?' Professor Umbridge asked Snape.

'Yes,' said Snape quietly.

'But you were unsuccessful?'

Snape's lip curled.

'Obviously'

Professor Umbridge scribbled on her clipboard.

'And you have applied regularly for the Defence Against the Dark Arts post since you first joined the school, I believe?'

'Yes,' said Snape quietly, barely moving his lips. He looked very angry.

'Do you have any idea why Dumbledore has consistently refused to appoint you?' asked Umbridge.

'I suggest you ask him,' said Snape jerkily. .?

'Oh, I shall,' said Professor Umbridge, with a sweet smile.

'I suppose this is relevant?' Snape asked, his black eyes narrowed.

'Oh yes,' said Professor Umbridge, 'yes, the Ministry wants a thorough understanding of teachers' - er - backgrounds.'

She turned away, walked over to Pansy Parkinson and began questioning her about the lessons. Snape looked round at Harry and their eyes met for a second. Harry hastily dropped his gaze to his potion, which was now congealing foully and giving off a strong smell of burned rubber.

'No marks again, then, Potter,' said Snape maliciously, emptying Harry's cauldron with a wave of his wand. 'You will write me an essay on the correct composition of this potion, indicating how and why you went wrong, to be handed in next lesson, do you understand?'

'Yes,' said Harry furiously. Snape had already given them homework and he had Quidditch practice this evening; this would mean another couple of sleepless nights. It did not seem possible that he had awoken that morning feeling very happy. All he felt now was a fervent desire for this day to end.

'Maybe I'll skive off Divination,' he said glumly, as they stood in the courtyard after lunch, the wind whipping at the hems of robes and brims of hats. I'll pretend to be ill and do Snape's essay instead, then I won't have to stay up half the night.'

There was too much truth in this to ignore, so half an hour later Harry took his seat in the hot, overperfumed atmosphere of the Divination classroom, feeling angry at everybody. Professor Trelawney was yet again handing out copies of The Dream Oracle. Harry thought he'd surely be much better employed doing Snape's punishment essay than sitting here trying to find meaning in a lot of made-up dreams.

'Well,' said Hermione, 'look on the bright side - at least now you'll have time to do Snape's essay!'

First, Fred would take a bite out of the orange end of a chew, at which he would vomit spectacularly into a bucket they had placed in front of them. Then he would force down the purple end of the chew, at which the vomiting would immediately cease. Lee Jordan, who was assisting the demonstration, was lazily Vanishing the vomit at regular intervals with the same Vanishing Spell Snape kept using on Harrys potions.

For a moment Harry was tempted to go with Dobby. He was halfway out of his seat, intending to hurry upstairs for his Invisibility Cloak when, not for the first time, a voice very much like Hermione's whispered in his ear: reckless. It was, after all, very late, he was exhausted, and had Snape's essay to finish.

'I think you've got enough to be getting on with at the moment,' she said loftily. Nobody could quite believe their ears until she looked directly at Harry and Ron and said grimly, 'I've become accustomed to seeing the Quidditch Cup in my study, boys, and I really don't want to have to hand it over to Professor Snape, so use the extra time to practise, won't you?'

Snape was no less obviously partisan; he had booked the Quidditch pitch for Slytherin practice so often that the Gryffindors had difficulty getting on it to play. He was also turning a deaf ear to the many reports of Slytherin attempts to hex Gryffindor players in the corridors. When Alicia Spinnet turned up in the hospital wing with her eyebrows growing so thick and fast they obscured her vision and obstructed her mouth, Snape insisted that she must have attempted a Hair-thickening Charm on herself and refused to listen to the fourteen eye-witnesses who insisted they had seen the Slytherin Keeper, Miles Bletchley, hit her from behind with a jinx while she worked in the library.

Harry would have given a great deal to be making as much progress at Occlumency as Neville was making during the DA meetings. Harry's sessions with Snape, which had started badly enough, were not improving. On the contrary Harry felt he was getting worse with every lesson.

Before he had started studying Occlumency, his scar had prickled occasionally, usually during the night, or else following one of those strange flashes of Voldemort's thoughts or mood that he experienced every now and then. Nowadays, however, his scar hardly ever stopped prickling, and he often felt lurches of annoyance or cheerfulness that were unrelated to what was happening to him at the time, which were always accompanied by a particularly painful twinge from his scar. He had the horrible impression that he was slowly turning into a kind of aerial that was tuned in to tiny fluctuations in Voldemorts mood, and he was sure he could date this increased sensitivity firmly from his first Occlumency lesson with Snape. What was more, he was now dreaming about walking down the corridor towards the entrance to the Department of Mysteries almost every night, dreams which always culminated in him standing longingly in front of the plain black door.

'Maybe it's a bit like an illness,' said Hermione, looking concerned when Harry confided in her and Ron. 'A fever or something. It has to get worse before it gets better.'

The lessons with Snape are making it worse,' said Harry flatly. 'I'm getting sick of my scar hurting and I'm getting bored with walking down that corridor every night.' He rubbed his forehead angrily. 'I just wish the door would open, I'm sick of standing staring at it -'

That's not funny,' said Hermione sharply. 'Dumbledore doesn't want you to have dreams about that corridor at all, or he wouldn't have asked Snape to teach you Occlumency. You're just going to have to work a bit harder in your lessons.'

'I am working!' said Harry nettled. 'You try it some time - Snape trying to get inside your head -- it's not a bundle of laughs, you know!'

'Maybe…' said Ron slowly.

'Maybe what?' said Hermione, rather snappishly.

'Maybe it's not Harry's fault he can't close his mind,' said Ron darkly.

'What do you mean?' said Hermione.

'Well, maybe Snape isn't really trying to help Harry…'

Harry and Hermione stared at him. Ron looked darkly and meaningfully from one to the other.

'Maybe,' he said again, in a lower voice, 'he's actually trying to open Harry's mind a bit wider… make it easier for You-Know-'

'Shut up, Ron,' said Hermione angrily. 'How many times have you suspected Snape, and when have you ever been right? Dumbledore trusts him, he works for the Order, that ought to be enough.'

'He used to be a Death Eater,' said Ron stubbornly. 'And we've never seen proof that he really swapped sides.'

'Dumbledore trusts him,' Hermione repeated. 'And if we can't trust Dumbledore, we can't trust anyone.'

With so much to worry about and so much to do - startling amounts of homework that frequently kept the fifth-years working until past midnight, secret DA sessions and regular classes with Snape -January seemed to be passing alarmingly fast. Before Harry knew it, February had arrived, bringing with it wetter and warmer weather and the prospect of the second Hogsmeade visit of the year. Harry had had very little time to spare for conversations with Cho since they had agreed to visit the village together, but suddenly found himself facing a Valentine's Day spent entirely in her company.

Umbridge had been sitting a few rows below Harry and Hermione. Once or twice she had turned squatly in her seat to look at him, her wide toad's mouth stretched in what he thought had been a gloating smile. The memory of it made him feel hot with anger as he lay there in the dark. After a few minutes, however, he remembered that he was supposed to be emptying his mind of all emotion before he slept, as Snape kept instructing him at the end of every Occlumency lesson.

He tried for a moment or two, but the thought of Snape on top of memories of Umbridge merely increased his sense of grumbling resentment and he found himself focusing instead on how much he loathed the pair of them. Slowly, Ron's snores died away, to be replaced by the sound of deep, slow breathing. It took Harry much longer to get to sleep; his body was tired, but it took his brain a long time to close down.

'I haven't got to tell anyone,' said Harry shortly. '1 wouldn't have seen it at all if I could do Occlumency. I'm supposed to have learned to shut this stuff out. That's what they want.'

Unfortunately, the back of his mind was no longer the secure place it had once been.

'Get up, Potter.'

A couple of weeks after his dream of Rookwood, Harry was to be found, yet again, kneeling on the floor of Snape's office, trying to clear his head. He had just been forced, yet again, to relive a stream of very early memories he had not even realised he still had, most of them concerning humiliations Dudley and his gang had inflicted upon him in primary school.

That last memory,' said Snape. 'What was it?'

'I don't know,' said Harry, getting wearily to his feet. He was finding it increasingly difficult to disentangle separate memories from the rush of images and sound that Snape kept calling forth. 'You mean the one where my cousin tried to make me stand in the toilet?'

'No,' said Snape softly. 'I mean the one with a man kneeling in the middle of a darkened room…'

'It's… nothing,' said Harry.

Snape's dark eyes bored into Harry's. Remembering what Snape had said about eye contact being crucial to Legilimency, Harry blinked and looked away.

'How do that man and that room come to be inside your head, Potter?' said Snape.

'It -' said Harry, looking everywhere but at Snape, 'it was -just a dream I had.'

'A dream?' repeated Snape.

There was a pause during which Harry stared fixedly at a large dead frog suspended in a jar of purple liquid.

'You do know why we are here, don't you, Potter?' said Snape, in a low, dangerous voice. 'You do know why I am giving up my evenings to this tedious job?'

'Yes,' said Harry stiffly.

'Remind me why we are here, Potter.'

'So I can learn Occlumency,' said Harry, now glaring at a dead eel.

'Correct, Potter. And dim though you may be -' Harry looked back at Snape, hating him '- I would have thought that after over two months of lessons you might have made some progress. How many other dreams about the Dark Lord have you had?'

'Just that one,' lied Harry.

'Perhaps,' said Snape, his dark, cold eyes narrowing slightly, 'perhaps you actually enjoy having these visions and dreams, Potter. Maybe they make you feel special - important?'

'No, they don't,' said Harry, his jaw set and his fingers clenched tightly around the handle of his wand.

That is just as well, Potter,' said Snape coldly, 'because you are neither special nor important, and it is not up to you to find out what the Dark Lord is saying to his Death Eaters.'

'No - that's your job, isn't it?' Harry shot at him.

He had not meant to say it; it had burst out of him in temper. For a long moment they stared at each other, Harry convinced he had gone too far. But there was a curious, almost satisfied expression on Snape's face when he answered.

'Yes, Potter,' he said, his eyes glinting. That is my job. Now, if you are ready, we will start again.'

He raised his wand: 'One - two - three - Legilimensl'

A hundred Dementors were swooping towards Harry across the lake in the grounds… he screwed up his face in concentration… they were coming closer… he could see the dark holes beneath their hoods… yet he could also see Snape standing in front of him, his eyes fixed on Harry's face, muttering under his breath… and somehow, Snape was growing clearer, and the Dementors were growing fainter…

Harry raised his own wand.

'Protego!'

Snape staggered - his wand flew upwards, away from Harry -and suddenly Harry's mind was teeming wwith memories that were not his: a hook-nosed man was shouting at a cowering woman, while a small dark-haired boy cried in a corner… a greasy-haired teenager sat alone in a dark bedroom, pointing his wand at the ceiling, shooting down flies… a girl was laughing as a scrawny boy tried to mount a bucking broomstick -

'ENOUGH!'

Harry felt as though he had been pushed hard in the chest; he staggered several steps backwards, hit some of the shelves covering Snape's walls and heard something crack. Snape was shaking slightly, and was very white in the face.

The back of Harry's robes was damp. One of the jars behind him had broken when he fell against it; the pickled slimy thing within was swirling in its draining potion.

'Reparo,' hissed Snape, and the jar sealed itself at once. 'Well, Potter… that was certainly an improvement…' Panting slightly, Snape straightened the Pensieve in which he had again stored some of his thoughts before starting the lesson, almost as though he was checking they were still there. 'I don't remember telling you to use a Shield Charm… but there is no doubt that it was effective…'

Harry did not speak; he felt that to say anything might be dangerous. He was sure he had just broken into Snape's memories, that he had just seen scenes from Snape's childhood. It was unnerving to think that the little boy who had been crying as he watched his parents shouting was actually standing in front of him with such loathing in his eyes.

'Let's try again, shall we?' said Snape.

Harry felt a thrill of dread; he was about to pay for what had just happened, he was sure of it. They moved back into position with the desk between them, Harry feeling he was going to find it much harder to empty his mind this time.

'On the count of three, then,' said Snape, raising his wand once more. 'One - two -'

Harry did not have time to gather himself together and attempt to clear his mind before Snape cried, 'Legilimens!'

He was hurtling along the corridor towards the Department of Mysteries, past the blank stone walls, past the torches - the plain black door was growing ever larger; he was moving so fast he was going to collide with it, he was feet from it and again he could see that chink of faint blue light -

The door had flown open! He was through it at last, inside a black-walled, black-floored circular room lit with blue-flamed candles, and there were more doors all around him - he needed to go on - but which door ought he to take -?

'POTTER!'

Harry opened his eyes. He was flat on his back again with no memory of having got there; he was also panting as though he really had run the length of the Department of Mysteries corridor, really had sprinted through the black door and found the circular room.

'Explain yourself!' said Snape, who was standing over him, looking furious.

'I… dunno what happened,' said Harry truthfully, standing up. There was a lump on the back of his head from where he had hit the ground and he felt feverish. 'I've never seen that before. I mean, I told you, I've dreamed about the door… but it's never opened before

'You are not working hard enough!'

For some reason, Snape seemed even angrier than he had done two minutes before, when Harry had seen into his teacher's memories.

'You are lazy and sloppy, Potter, it is small wonder that the Dark Lord -'

'Can you tell me something, sir?' said Harry, firing up again. 'Why do you call Voldemort the Dark Lord? I've only ever heard Death Eaters call him that.'

Snape opened his mouth in a snarl - and a woman screamed from somewhere outside the room.

Snapes head jerked upwards; he was gazing at the ceiling.

'What the -?' he muttered.

Harry could hear a muffled commotion coming from what he thought might be the Entrance Hall. Snape looked round at him, frowning.

'Did you see anything unusual on your way down here, Potter?'

Harry shook his head. Somewhere above them, the woman screamed again. Snape strode to his office door, his wand still held at the ready, and swept out of sight. Harry hesitated for a moment, then followed.

'Listen to me, Harry,' he said urgently. 'You must study Occlumency as hard as you can, do you understand me? Do everything Professor Snape tells you and practise it particularly every night before sleeping so that you can close your mind to bad dreams - you will understand why soon enough, but you must promise me -'

The man called Dawlish was stirring. Dumbledore seized Harry's wrist.

'Remember - close your mind -'

Harry spent the whole of the next day dreading what Snape was going to say if he found out how much further into the Department of Mysteries Harry had penetrated during his last dream. With a surge of guilt he realised that he had not practised Occlumency once since their last lesson: there had been too much going on since Dumbledore had left; he was sure he would not have been able to empty his mind even if he had tried. He doubted, however, whether Snape would accept that excuse.

He attempted a little last-minute practice during classes that day, but it was no good. Hermione kept asking him what was wrong whenever he fell silent trying to rid himself of all thought and emotion and, after all, the best moment to empty his brain was not while teachers were firing revision questions at the class.

Resigned to the worst, he set off for Snape's office after dinner. Halfway across the Entrance Hall, however, Cho came hurrying up to him.

'Over here,' said Harry, glad of a reason to postpone his meeting with Snape, and beckoning her across to the corner of the Entrance Hall where the giant hour-glasses stood. Gryffindor's was now almost empty. 'Are you OK? Umbridge hasn't been asking you about the DA, has she?'

Fuming, Harry descended the stairs to Snape's dungeon and, though he knew from experience how much easier it would be for Snape to penetrate his mind if he arrived angry and resentful, he succeeded in nothing but thinking of a few more things he should have said to Cho about Marietta before reaching the dungeon door.

'You're late, Potter,' said Snape coldly, as Harry closed the door behind him.

Snape was standing with his back to Harry, removing, as usual, certain of his thoughts and placing them carefully in Dumbledores Pensieve. He dropped the last silvery strand into the stone basin and turned to face Harry.

'So,' he said. 'Have you been practising?'

'Yes,' Harry lied, looking carefully at one of the legs of Snape's desk.

'Well, we'll soon find out, won't we?' said Snape smoothly. 'Wand out, Potter.'

Harry moved into his usual position, facing Snape with the desk between them. His heart was pumping fast with anger at Cho and anxiety about how much Snape was about to extract from his mind.

'On the count of three then,' said Snape lazily. 'One - two -'

Snape's office door banged open and Draco Malfoy sped in.

'Professor Snape, sir - oh - sorry -'

Malfoy was looking at Snape and Harry in some surprise.

'It's all right, Draco,' said Snape, lowering his wand. 'Potter is here for a little remedial Potions.'

Harry had not seen Malfoy look so gleeful since Umbridge had turned up to inspect Hagrid.

'I didn't know,' he said, leering at Harry, who knew his face was burning. He would have given a great deal to be able to shout the truth at Malfoy - or, even better, to hit him with a good curse.

'Well, Draco, what is it?' asked Snape.

'It's Professor Umbridge, sir - she needs your help,' said Malfoy.

They've found Montague, sir, he's turned up jammed inside a toilet on the fourth floor.'

'How did he get in there?' demanded Snape.

'I don't know, sir, he's a bit confused.'

'Very well, very well. Potter,' said Snape, 'we shall resume this lesson tomorrow evening.'

He turned and swept from his office. Malfoy mouthed, 'Remedial Potions?' at Harry behind Snape's back before following him.

Seething, Harry replaced his wand inside his robes and made to leave the room. At least he had twenty-four more hours in which to practise; he knew he ought to feel grateful for the narrow escape, though it was hard that it came at the expense of Malfoy telling the whole school that he needed remedial Potions.

He was at the office door when he saw it: a patch of shivering light dancing on the doorframe. He stopped, and stood looking at it, reminded of something… then he remembered: it was a little like the lights he had seen in his dream last night, the lights in the second room he had walked through on his journey through the Department of Mysteries.

He turned around. The light was coming from the Pensieve sitting on Snape's desk. The silver-white contents were ebbing and swirling within. Snape's thoughts… things he did not want Harry to see if he broke through Snape's defences accidentally…

Harry gazed at the Pensieve, curiosity welling inside him… what was it that Snape was so keen to hide from Harry?

The silvery lights shivered on the wall… Harry took two steps towards the desk, thinking hard. Could it possibly be information about the Department of Mysteries that Snape was determined to keep from him?

Harry looked over his shoulder, his heart now pumping harder and faster than ever. How long would it take Snape to release Montague from the toilet? Would he come straight back to his office afterwards, or accompany Montague to the hospital wing? Surely the latter… Montague was Captain of the Slytherin Quidditch team, Snape would want to make sure he was all right.

Harry walked the remaining few feet to the Pensieve and stood over it, gazing into its depths. He hesitated, listening, then pulled out his wand again. The office and the corridor beyond were completely silent. He gave the contents of the Pensieve a small prod with the end of his wand.

The silvery stuff within began to swirl very fast. Harry leaned forwards over it and saw that it had become transparent. He was, once again, looking down into a room as though through a circular window in the ceiling… in fact, unless he was much mistaken, he was looking down into the Great Hall.

His breath was actually fogging the surface of Snape's thoughts… his brain seemed to be in limbo… it would be insane to do the thing he was so strongly tempted to do… he was trembling… Snape could be back at any moment… but Harry thought of Chos anger, of Malfoy's jeering face, and a reckless daring seized him.

He took a great gulp of breath, and plunged his face into the surface of Snape's thoughts. At once, the floor of the office lurched, tipping Harry head-first into the Pensieve…

'Well, I think we should just try and forget what you saw,' said Hermione firmly. 'And you ought to put in a bit more effort on your Occlumency from now on.'

'You are trying to block your mind, aren't you?' said Hermione, looking beadily at Harry. 'You are keeping going with your Occlumency?'

'Of course I am,' said Harry, trying to sound as though this question was insulting, but not quite meeting her eye. The truth was he was so intensely curious about what was hidden in that room full of dusty orbs, that he was quite keen for the dreams to continue.

'You don't get it!' Harry shouted at her, 'I'm not having nightmares, I'm not just dreaming! What d'you think all the Occlumency was for, why d'you think Dumbledore wanted me prevented from seeing these things? Because they're REAL, Hermione - Sirius is trapped, I've seen him. Voldemort's got him, and no one else knows, and that means we're the only ones who can save him, and if you don't want to do it, fine, but I'm going, understand? And if I remember rightly, you didn't have a problem with my saving-people thing when it was you I was saving from the Dementors, or -' he rounded on Ron '- when it was your sister I was saving from the Basilisk -'

'I never said I had a problem!' said Ron heatedly.

'But Harry, you've just said it,' said Hermione fiercely, 'Dumbledore wanted you to learn to shut these things out of your mind, if you'd done Occlumency properly you'd never have seen this -'

Glittering pink and silver winged piglets were now soaring past the windows of Gryffindor Tower. Harry lay and listened to the appreciative whoops of Gryffindors in the dormitories below them. His stomach gave a sickening jolt as he remembered that he had Occlumency the following evening.

Sunshine was streaming through the high windows on to the bent heads, which shone chestnut and copper and gold in the bright light. Harry looked around carefully. Snape had to be here somewhere… this was his memory…

And there he was, at a table right behind Harry. Harry stared. Snape-the-teenager had a stringy, pallid look about him, like a plant kept in the dark. His hair was lank and greasy and was flopping on to the table, his hooked nose barely half an inch from the surface of the parchment as he scribbled. Harry moved around behind Snape and read the heading of the examination paper: DEFENCE AGAINST THE DARK ARTS - ORDINARY WIZARDING LEVEL.

So Snape had to be fifteen or sixteen, around Harry's own age. His hand was flying across the parchment; he had written at least a foot more than his closest neighbours, and yet his writing was minuscule and cramped.

Harry looked around and glimpsed Snape a short way away, moving between the tables towards the doors to the Entrance Hall, still absorbed in his own exam paper. Round-shouldered yet angular, he walked in a twitchy manner that recalled a spider, and his oily hair was jumping about his face.

A gang of chattering girls separated Snape from James, Sirius and Lupin, and by planting himself in their midst, Harry managed to keep Snape in sight while straining his ears to catch the voices of James and his friends.

Harry looked anxiously behind him again. Snape remained close by, still buried in his exam questions - but this was Snape's memory and Harry was sure that if Snape chose to wander off in a different direction once outside in the grounds, he, Harry, would not be able to follow James any further. To his intense relief, however, when James and his three friends strode off down the lawn towards the lake, Snape followed, still poring over the exam paper and apparently with no fixed idea of where he was going. By keeping a little ahead of him, Harry managed to maintain a close watch on James and the others.

They stopped in the shade of the very same beech tree on the edge of the lake where Harry, Ron and Hermione had once spent a Sunday finishing their homework, and threw themselves down on the grass. Harry looked over his shoulder yet again and saw, to his delight, that Snape had settled himself on the grass in the dense shadow of a clump of bushes. He was as deeply immersed in the OWL paper as ever, which left Harry free to sit down on the grass between the beech and the bushes and watch the foursome under the tree. The sunlight was dazzling on the smooth surface of the lake, on the bank of which the group of laughing girls who had just left the Great Hall were sitting, with their shoes and socks off, cooling their feet in the water.

This'll liven you up, Padfoot,' said James quietly. 'Look who it is…'

Sirius's head turned. He became very still, like a dog that has scented a rabbit.

'Excellent,' he said softly. 'Snivellus.'

Harry turned to see what Sirius was looking at.

Snape was on his feet again, and was stowing the OWL paper in his bag. As he left the shadows of the bushes and set off across the grass, Sirius and James stood up.

Lupin and Wormtail remained sitting: Lupin was still staring down at his book, though his eyes were not moving and a faint frown line had appeared between his eyebrows; Wormtail was looking from Sirius and James to Snape with a look of avid anticipation on his face.

'All right, Snivellus?' said James loudly.

Snape reacted so fast it was as though he had been expecting an attack: dropping his bag, he plunged his hand inside his robes and his wand was halfway into the air when James shouted, 'Expelliarmus!'

Snape's wand flew twelve feet into the air and fell with a little thud in the grass behind him. Sirius let out a bark of laughter.

'Impedimenta!' he said, pointing his wand at Snape, who was knocked off his feet halfway through a dive towards his own fallen wand.

Students all around had turned to watch. Some of them had got to their feet and were edging nearer. Some looked apprehensive, others entertained.

Snape lay panting on the ground. James and Sirius advanced on him, wands raised, James glancing over his shoulder at the girls at the water's edge as he went. Wormtail was on his feet now, watching hungrily, edging around Lupin to get a clearer view.

'How'd the exam go, Snivelly?' said James.

'I was watching him, his nose was touching the parchment,' said Sirius viciously. There'll be great grease marks all over it, they won't be able to read a word.'

Several people watching laughed; Snape was clearly unpopular. Wormtail sniggered shrilly. Snape was trying to get up, but the jinx was still operating on him; he was struggling, as though bound by invisible ropes.

'You - wait,' he panted, staring up at James with an expression of purest loathing, 'you - wait!'

'Wait for what?' said Sirius coolly. 'What're you going to do, Snivelly, wipe your nose on us?'

Snape let out a stream of mixed swear words and hexes, but with his wand ten feet away nothing happened.

'Wash out your mouth,' said James coldly. 'Scourgify!'

Pink soap bubbles streamed from Snape's mouth at once; the froth was covering his lips, making him gag, choking him -

'Leave him ALONE!'

James and Sirius looked round. James's free hand immediately jumped to his hair.

It was one of the girls from the lake edge. She had thick, dark red hair that fell to her shoulders, and startlingly green almond-shaped eyes - Harry's eyes.

Harry's mother.

'All right, Evans?' said James, and the tone of his voice was suddenly pleasant, deeper, more mature.

'Leave him alone,' Lily repeated. She was looking at James with every sign of great dislike. 'What's he done to you?'

'Well,' said James, appearing to deliberate the point, 'it's more the fact that he exists, if you know what I mean…'

Many of the surrounding students laughed, Sirius and Wormtail included, but Lupin, still apparently intent on his book, didn't, and nor did Lily.

'You think you're funny,' she said coldly. 'But you're just an arrogant, bullying toerag, Potter. Leave him alone.'

'I will if you go out with me, Evans,' said James quickly. 'Go on… go out with me and I'll never lay a wand on old Snivelly again.'

Behind him, the Impediment Jinx was wearing off. Snape was beginning to inch towards his fallen wand, spitting out soapsuds as he crawled.

'I wouldn't go out with you if it was a choice between you and the giant squid,' said Lily.

'Bad luck, Prongs,' said Sirius briskly, and turned back to Snape. 'OI!'

But too late; Snape had directed his wand straight at James; there was a flash of light and a gash appeared on the side of James's face, spattering his robes with blood. James whirled about: a second flash of light later, Snape was hanging upside-down in the air, his robes falling over his head to reveal skinny, pallid legs and a pair of greying underpants.

Many people in the small crowd cheered; Sirius, James and Wormtail roared with laughter.

Lily, whose furious expression had twitched for an instant as though she was going to smile, said, 'Let him down!'

'Certainly,' said James and he jerked his wand upwards; Snape fell into a crumpled heap on the ground. Disentangling himself from his robes he got quickly to his feet, wand up, but Sirius said, 'Petrificus Totalus!' and Snape keeled over again, rigid as a board.

'LEAVE HIM ALONE!' Lily shouted. She had her own wand out now. James and Sirius eyed it warily.

'Ah, Evans, don't make me hex you,' said James earnestly.

Take the curse off him, then!'

James sighed deeply, then turned to Snape and muttered the counter-curse.

There you go,' he said, as Snape struggled to his feet. 'You're lucky Evans was here, Snivellus -'

'I don't need help from filthy little Mudbloods like her!'

Lily blinked.

'Fine,' she said coolly. 'I won't bother in future. And I'd wash your pants if I were you, Snivellus.'

'Apologise to Evans!' James roared at Snape, his wand pointed threateningly at him.

'I don't want you to make him apologise,' Lily shouted, rounding on James. 'You're as bad as he is.'

'What?' yelped James. I'd NEVER call you a - you-know-what!'

'Messing up your hair because you think it looks cool to look like you've just got off your broomstick, showing off with that stupid Snitch, walking down corridors and hexing anyone who annoys you just because you can - I'm surprised your broomstick can get off the ground with that fat head on it. You make me SICK.'

'Right,' said James, who looked furious now, 'right -'

There was another flash of light, and Snape was once again hanging upside-down in the air.

'Who wants to see me take off Snivelly's pants?'

But whether James really did take off Snapes pants, Harry never found out. A hand had closed tight over his upper arm, closed with a pincer-like grip. Wincing, Harry looked round to see who had hold of him, and saw, with a thrill of horror, a fully grown, adult-sized Snape standing right beside him, white with rage.

'Having fun?'

Harry felt himself rising into the air; the summer's day evaporated around him; he was floating upwards through icy blackness, Snape's hand still tight upon his upper arm. Then, with a swooping feeling as though he had turned head-over-heels in midair, his feet hit the stone floor of Snape's dungeon and he was standing again beside the Pensieve on Snape's desk in the shadowy, present-day Potion masters study.

'So,' said Snape, gripping Harry's arm so tightly Harry's hand was starting to feel numb. 'So… been enjoying yourself, Potter?'

'N-no,' said Harry, trying to free his arm.

It was scary: Snape's lips were shaking, his face v:as white, his teeth were bared.

'Amusing man, your father, wasn't he?' said Snape, shaking Harry so hard his glasses slipped down his nose.

'I - didn't -'

Snape threw Harry from him with all his might. Harry fell hard on to the dungeon floor. <;

'You will not repeat what you saw to anybody!' Snape bellowed.

'No,' said Harry, getting to his feet as far from Snape as he could. 'No, of course I w-'

'Get out, get out, I don't want to see you in this office ever again!'

And as Harry hurtled towards the door, a jar of dead cockroaches exploded over his head. He wrenched the door open and flew along the corridor, stopping only when he had put three floors between himself and Snape. There he leaned against the wall, panting, and rubbing his bruised arm.

He had no desire at all to return to Gryffindor Tower so early, nor to tell Ron and Hermione what he had just seen. What was making Harry feel so horrified and unhappy was not being shouted at or having jars thrown at him; it was that he knew how it felt to be humiliated in the middle of a circle of onlookers, knew exactly how Snape had felt as his father had taunted him, and that judging from what he had just seen, his father had been every bit as arrogant as Snape had always told him.

Careers Advice

'But why haven't you got Occlumency lessons any more?' said Hermione, frowning.

'I've told you,' Harry muttered. 'Snape reckons I can carry on by myself now I've got the basics.'

'So you've stopped having funny dreams?' said Hermione sceptically.

'Pretty much,' said Harry, not looking at her.

'Well, I don't think Snape should stop until you're absolutely sure you can control them!' said Hermione indignantly. 'Harry, I think you should go back to him and ask -'

'No,' said Harry forcefully. 'Just drop it, Hermione, OK?'

Ron went into a rant about Marietta Edgecombe, which Harry found helpful; all he had to do was look angry, nod and say 'Yeah' and That's right' whenever Ron drew breath, leaving his mind free to dwell, ever more miserably, on what he had seen in the Pensieve.

He felt as though the memory of it was eating him from inside. He had been so sure his parents were wonderful people that he had never had the slightest difficulty in disbelieving the aspersions Snape cast on his father's character. Hadn't people like Hagrid and Sirius told Harry how wonderful his father had been? (Yeah, well, look what Sirius was like himself, said a nagging voice inside Harry's head… he was as bad, wasn't he?) Yes, he had once overheard Professor McGonagall saying that his father and Sirius had been troublemakers at school, but she had described them as forerunners of the Weasley twins, and Harry could not imagine Fred and George dangling someone upside-down for the fun of it… not unless they really loathed them… perhaps Malfoy, or somebody who really deserved it…

Harry tried to make a case for Snape having deserved what he had suffered at James's hands: but hadn't Lily asked, 'What's he done to you?' And hadn't James replied, 'It's more the fact that he exists, if you know what I mean.' Hadn't James started it all simply because Sirius had said he was bored? Harry remembered Lupin saying back in Grimmauld Place that Dumbledore had made him prefect in the hope that he would be able to exercise some control over James and Sirius… but in the Pensieve, he had sat there and let it all happen…

Harry awoke very early the next day, feeling almost as anxious as he had done on the morning of his disciplinary hearing at the Ministry of Magic. It was not only the prospect of breaking into Umbridge's office and using her fire to speak to Sirius that was making him feel nervous, though that was certainly bad enough; today also happened to be the first time Harry would be in close proximity to Snape since Snape had thrown him out of his office.

After lying in bed for a while thinking about the day ahead, Harry got up very quietly and moved across to the window beside Nevilles bed, and stared out on a truly glorious morning. The sky was a clear, misty, opalescent blue. Directly ahead of him, Harry could see the towering beech tree below which his father had once tormented Snape. He was not sure what Sirius could possibly say to him that would make up for what he had seen in the Pensieve, but he was desperate to hear Sirius's own account of what had happened, to know of any mitigating factors there might have been, any excuse at all for his father's behaviour…

Snape, meanwhile, seemed to have decided to act as though Harry were invisible. Harry was, of course, well-used to this tactic, as it was one of Uncle Vernon's favourites, and on the whole was grateful he had to suffer nothing worse. In fact, compared to what he usually had to endure from Snape in the way of taunts and snide remarks, he found the new approach something of an improvement, and was pleased to find that when left well alone, he was able to concoct an Invigoration Draught quite easily. At the end of the lesson he scooped some of the potion into a flask, corked it and took it up to Snape's desk for marking, feeling that he might at last have scraped an '£'.

He had just turned away when he heard a smashing noise. Malfoy gave a gleeful yell of laughter. Harry whipped around. His potion sample lay in pieces on the floor and Snape was surveying him with a look of gloating pleasure.

'Whoops,' he said softly. 'Another zero, then, Potter.'

Harry was too incensed to speak. He strode back to his cauldron, intending to fill another flask and force Snape to mark it, but saw to his horror that the rest of the contents had vanished.

'I would also advise Transfiguration, because Aurors frequently need to Transfigure or Untransfigure in their work. And I ought to tell you now, Potter, that I do not accept students into my NEWT classes unless they have achieved "Exceeds Expectations" or higher at Ordinary Wizarding Level. I'd say you're averaging "Acceptable" at the moment, so you'll need to put in some good hard work before the exams to stand a chance of continuing. Then you ought to do Charms, always useful, and Potions. Yes, Potter, Potions,' she added, with the merest flicker of a smile. 'Poisons and antidotes are essential study for Aurors. And I must tell you that Professor Snape absolutely refuses to take students who get anything other than "Outstanding" in their OWLs, so -'

'Look, Harry' said Sirius placatingly, 'James and Snape hated each other from the moment they set eyes on each other, it was just one of those things, you can understand that, can't you? I think James was everything Snape wanted to be - he was popular, he was good at Quidditch - good at pretty much everything. And Snnape was just this little oddball who was up to his eyes in the Dark Arts, and James - whatever else he may have appeared to you, Harry - always hated the Dark Arts.'

'Yeah,' said Harry, 'but he just attacked Snape for no good reason, just because - well, just because you said you were bored,' he finished, with a slightly apologetic note in his voice.

'I'm not proud of it,' said Sirius quickly.

'Of course he was a bit of an idiot!' said Sirius bracingly, 'we were all idiots! Well - not Moony so much,' he said fairly, looking at Lupin.

But Lupin shook his head. 'Did I ever tell you to lay off Snape?' he said. 'Did I ever have the guts to tell you I thought you were out of order?'

'Yeah, well,' said Sirius, 'you made us feel ashamed of ourselves sometimes… that was something…"

'Once James had deflated his head a bit,' said Sirius.

'And stopped hexing people just for the fun of it,' said Lupin.

'Even Snape?' said Harry.

Well,' said Lupin slowly, 'Snape was a special case. I mean, he never lost an opportunity to curse James so you couldn't really expect James to take that lying down, could you?'

'And my mum was OK with that?'

'She didn't know too much about it, to tell you the truth,' said Sirius. '1 mean, James didn't take Snape on dates with her and jinx him in front of her, did he?'

Sirius frowned at Harry, who was still looking unconvinced.

'Look,' he said, 'your father was the best friend I ever had and he was a good person. A lot of people are idiots at the age of fifteen. He grew out of it.'

'Yeah, OK,' said Harry heavily. 'I just never thought I'd feel sorry for Snape.'

'Now you mention it,' said Lupin, a faint crease between his eyebrows, 'how did Snape react when he found you'd seen all this?'

'He told me he'd never teach me Occlumency again,' said Harry indifferently, 'like that's a big disappoint-'

'He WHAT?' shouted Sirius, causing Harry to jump and inhale a mouthful of ashes.

'Are you serious, Harry?' said Lupin quickly. 'He's stopped giving you lessons?'

'Yeah,' said Harry, surprised at what he considered a great over-reaction. 'But it's OK, I don't care, it's a bit of a relief to tell you the -'

'I'm coming up there to have a word with Snape!' said Sirius forcefully, and he actually made to stand up, but Lupin wrenched him back down again.

'If anyone's going to tell Snape it will be me!' he said firmly. 'But Harry, first of all, you're to go back to Snape and tell him that on no account is he to stop giving you lessons - when Dumbledore hears -'

'I can't tell him that, he'd kill me!' said Harry, outraged. 'You didn't see him when we got out of the Pensieve.'

'Harry there is nothing so important as you learning Occlumency!' said Lupin sternly. 'Do you understand me? Nothing!'

'OK, OK,' said Harry, thoroughly discomposed, not to mention annoyed. Til… I'll try and say something to him… but it won't be-'

He fell silent. He could hear distant footsteps.

'No, I wasn't!' she said angrily. 'As a matter of fact, I was going to ask Harry when he's going to go back to Snape and ask for more Occlumency lessons!'

Harry's heart sank. Once they had exhausted the subject of Fred and George's dramatic departure, which admittedly had taken many hours, Ron and Hermione had wanted to hear news of Sirius. As Harry had not confided in them the reason he had wanted to talk to Sirius in the first place, it had been hard to think of what to tell them; he had ended up saying, truthfully, that Sirius wanted Harry to resume Occlumency lessons. He had been regretting this ever since; Hermione would not let the subject drop and kept reverting to it when Harry least expected it.

Their teachers were no longer setting them homework; lessons were devoted to revising those topics the teachers thought most likely to come up in the exams. The purposeful, feverish atmosphere drove nearly everything but the OWLs from Harry's mind, though he did wonder occasionally during Potions lessons whether Lupin had ever told Snape that he must continue giving Harry Occlumency tuition. If he had, then Snape had ignored Lupin as thoroughly as he was now ignoring Harry. This suited Harry very well; he was quite busy and tense enough without extra classes with Snape, and to his relief Hermione was much too preoccupied these days to badger him about Occlumency; she was spending a lot of time muttering to herself, and had not laid out any elf clothes for days.

Once breakfast was over, the fifth- and seventh-years milled around in the Entrance Hall while the other students went off to lessons; then, at half past nine, they were called forwards class by class to re-enter the Great Hall, which had been rearranged exactly as Harry had seen it in the Pensieve when his father, Sirius and Snape had been taking their OWLs; the four house tables had been removed and replaced instead with many tables for one, all facing the staff-table end of the Hall where Professor McGonagall stood facing them. When they were all seated and quiet, she said, 'You may begin,' and turned over an enormous hour-glass on the desk beside her, on which there were also spare quills, ink bottles and rolls of parchment.

The afternoon practical was not as dreadful as he had expected it to be. With Snape absent from the proceedings, he found that he was much more relaxed than he usually was while making potions. Neville, who was sitting very near Harry, also looked happier than Harry had ever seen him during a Potions class. When Professor Marchbanks said, 'Step away from your cauldrons, please, the examination is over,' Harry corked his sample flask feeling that he might not have achieved a good grade but he had, with luck, avoided a fail.

'Very well,' she said in her most dangerous and falsely sweet voice. 'Very well, Mr Potter… I offered you the chance to tell me freely. You refused. I have no alternative but to force you. Draco - fetch Professor Snape.'

Malfoy stowed Harry's wand inside his robes and left the room smirking, but Harry hardly noticed. He had just realised something; he could not believe he had been so stupid as to forget it. He had thought that all the members of the Order, all those who could help him save Sirius, were gone - but he had been wrong. There was still a member of the Order of the Phoenix at Hogwarts - Snape.

Harry looked back at Umbridge, who was watching him closely. He kept his face deliberately smooth and blank as footsteps were heard in the corridor outside and Draco Malfoy entered the room, closely followed by Snape.

'You wanted to see me, Headmistress?' said Snape, looking around at all the pairs of struggling students with an expression of complete indifference.

'Ah, Professor Snape,' said Umbridge, smiling widely and standing up again. 'Yes, 1 would like another bottle of Veritaserum, as quick as you can, please.'

'You took my last bottle to interrogate Potter,' he said, surveying her coolly through his greasy curtains of black hair. 'Surely you did not use it all? I told you that three drops would be sufficient.'

Umbridge flushed.

'You can make some more, can't you?' she said, her voice becoming more sweetly girlish as it always did when she was furious.

'Certainly,' said Snape, his lip curling. 'It takes a full moon-cycle to mature, so I should have it ready for you in around a month.'

'A month?' squawked Umbridge, swelling toadishly. 'A month? But I need it this evening, Snape! I have just found Potter using my fire to communicate with a person or persons unknown!'

'Really?' said Snape, showing his first, faint sign of interest as he looked round at Harry. 'Well, it doesn't surprise me. Potter has never shown much inclination to follow school rules.'

His cold, dark eyes were boring into Harry's, who met his gaze unflinchingly, concentrating hard on what he had seen in his dream, willing Snape to read it in his mind, to understand…

'I wish to interrogate him!' repeated Umbridge angrily, and Snape looked away from Harry back into her furiously quivering face. 'I wish you to provide me with a potion that will force him to tell me the truth!'

'I have already told you,' said Snape smoothly, 'that I have no further stocks of Veritaserum. Unless you wish to poison Potter -and I assure you I would have the greattest sympathy with you if you did - I cannot help you. The only trouble iss that most venoms act too fast to give the victim much time for truth-telling.'

Snape looked back at Harry, who stared at him, frantic to communicate without words.

Voldemort's got Sirius in the Department of Mysteries, he thought desperately. Voldemort's got Sirius -

'You are on probation!' shrieked Professor Umbridge, and Snape looked back at her, his eyebrows slightly raised. 'You are being deliberately unhelpful! I expected better, Lucius Malfoy always speaks most highly of you! Now get out of my office!'

Snape gave her an ironic bow and turned to leave. Harry knew his last chance of letting the Order know what was going on was walking out of the door.

'He's got Padfoot!' he shouted. 'He's got Padfoot at the place where it's hidden!'

Snape had stopped with his hand on Umbridges door handle.

'Padfoot?' cried Professor Umbridge, looking eagerly from Harry to Snape. 'What is Padfoot? Where what is hidden? What does he mean, Snape?'

Snape looked round at Harry. His face was inscrutable. Harry could not tell whether he had understood or not, but he did not dare speak more plainly in front of Umbridge.

'I have no idea,' said Snape coldly. 'Potter, when 1 want nonsense shouted at me I shall give you a Babbling Beverage. And Crabbe, loosen your hold a little. If Longbottom suffocates it will mean a lot of tedious paperwork and I am afraid I shall have to mention it on your reference if ever you apply for a job.'

He closed the door behind him with a snap, leaving Harry in a state of worse turmoil than before: Snape had been his very last hope. He looked at Umbridge, who seemed to be feeling the same way; her chest was heaving with rage and frustration.

`More recently' said Dumbledore, `I became concerned that Voldemort might realise that this connection between you exists. Sure enough, there came a time when you entered so far into his mind and thoughts that he sensed your presence. I am speaking, of course, of the night when you witnessed the attack on Mr Weasley'

`Yeah, Snape told me,' Harry muttered.

`Professor Snape, Harry' Dumbledore corrected him quietly. `But did you not wonder why it was not I who explained this to you? Why I did not teach you Occlumency? Why I had not so much as looked at you for months?'

`And then you saw Rockwood, who worked in the Department of Mysteries before his arrest, telling Voldemort what we had known all along -that the prophecies held in the Ministry of Magic are heavily protected. Only the people to whom they refer can lift them from the shelves without suffering madness: in this case, either Voldemort himself would have to enter the Ministry of Magic, and risk revealing himself at last - or else you would have to take it for him. It became a matter of even greater urgency that you should master Occlumency'

'Sirius told me you felt Voldemort awake inside you the very night that you had the vision of Arthur Weasley's attack. I knew at once that my worst fears were correct: Voldemort had realised he could use you. In an attempt to arm you against Voldemort's assaults on your mind, I arranged Occlumency lessons with Professor Snape.'

`Professor Snape discovered,' Dumbledore resumed, `that you had been dreaming about the door to the Department of Mysteries for months. Voldemort, of course, had been obsessed with the possibility of hearing the prophecy ever since he regained his body; and as he dwelled on the door, so did you, though you did not know what it meant.

`Kreacher told me last night,' said Dumbledore. `You see, when you gave Professor Snape that cryptic warning, he realised that you had had a vision of Sirius trapped in the bowels of the Department of Mysteries. He, like you, attempted to contact Sirius at once. I should explain that members of the Order of the Phoenix have more reliable methods of communicating than the fire in Dolores Umbridge's office. Professor Snape found that Sirius was alive and safe in Grimmauld Place.

`When, however, you did not return from your trip into the Forest with Dolores Umbridge, Professor Snape grew worried that you still believed Sirius to be a captive of Lord Voldemort's. He alerted certain Order members at once.'

Dumbledore heaved a great sigh and continued, `Alastor Moody, Nymphadora Tonks, Kingsley Shacklebolt and Remus Lupin were at Headquarters when he made contact. All agreed to go to your aid at once. Professor Snape requested that Sirius remain behind, as he needed somebody to remain at Headquarters to tell me what had happened, for I was due there at any moment. In the meantime he, Professor Snape, intended to search the Forest for you.

He was on his feet again, furious, ready to fly at Dumbledore, who had plainly not understood Sirius at all, how brave he was, how much he had suffered …

`What about Snape?' Harry spat. `You're not talking about him, are you? When I told him Voldemort had Sirius he just sneered at me as usual -

`Harry, you know Professor Snape had no choice but to pretend not to take you seriously in front of Dolores Umbridge,' said Dumbledore steadily, `but as I have explained, he informed the Order as soon as possible about what you had said. It was he who deduced where you had gone when you did not return from the Forest. It was he, too, who gave Professor Umbridge fake Veritaserum when she was attempting to force you to tell her Sirius's whereabouts.'

Harry disregarded this; he felt a savage pleasure in blaming Snape, it seemed to be easing his own sense of dreadful guilt, and he wanted to hear Dumbledore agree with him.

`Snape - Snape g - goaded Sirius about staying in the house - he made out Sirius was a coward =