Mrs Fisher from number twenty-two was on their doorstep again, complaining about their house alarm. Kathy and Alan had only had it for three weeks, but it kept going off all the time. The ear-shattering siren started early in the morning, and didn't fall silent again until Kathy or Alan came home from work to turn it off. Their neighbours were fast losing patience, and Kathy didn't blame them. It was a very loud alarm.
'We've had the installers check it three times,' Kathy told Mrs Fisher. 'They can't find anything wrong with it.'
'We don't know why it keeps going off,' Alan said. 'But we'll have it checked again.'
The installers were called in once more. 'Nothing wrong with it,' they declared, and promptly left.
When Kathy drove home from work the following day, she heard the siren wailing from three streets away. As she pulled into her road, she was greeted by the familiar sight of the blue light flashing over the neighbourhood.
This time it was both Mrs Fisher from number twenty-two and Mr Jenkins from number nineteen who came round to complain. Kathy apologised profusely and promised to get the problem sorted.
The installers came for the fifth time and still couldn't find a fault. And every day - except for Sunday, when Kathy and Alan didn't go to work and were too afraid to leave the house - they came home to find a crowd of angry neighbours on their doorstep.
'We'll just have to leave it switched off,' Kathy told Alan.
'What's the point of having a house alarm if you can't use it?' Alan said.
'Then you deal with the neighbours!' Kathy snapped, 'I've had enough!'
They didn't speak again for the rest of the evening. When they went to bed, they lay back to back like statues, deliberately not touching each other. Neither of them could sleep. Kathy eventually rolled over and Alan hugged her.
The following day, Alan returned to the house before Kathy, because Kathy had offered to work late that day - and every day until the mystery of the house alarm was solved. He found Mrs Fisher, Mr Jenkins, the elderly sisters from number twenty-five, and Mrs Philpotts from next door, all waiting for him as he got out of his car.
Alan tried to calm them, promising a thorough investigation. He even tried cracking a few jokes to try and lighten the mutinous mood. But he could tell that his neighbours had reached the end of their tether. And so had he.
He called the installers. He told the installers to dismantle the alarm and take it away. There was a week of blissful silence, and then installers from another company came to fit a new, more expensive alarm.
The next day, as Alan pulled into their road, every single resident in the area was standing in his front garden. The even louder alarm was wailing, and the blue flashing light was brighter than ever. Alan rushed into the house and turned it off. A cheer went up from the crowd.
That night, over dinner, Kathy and Alan tried to figure out why two separate alarms from two different companies would go off at almost the same time every day.
'Perhaps the house has a faulty electric circuit?' Alan suggested.
'They checked the wiring,' Kathy reminded him. 'The installers said something external must be setting it off.'
'But what?'
'Perhaps we have mice?'
'We don't have mice, Kathy.'
'Good.' She breathed a sigh of relief. 'Could it be spiders, do you think?'
'They'd have to be pretty big spiders to be picked up by the sensors.'
Kathy shuddered at the thought of giant eight-legged creatures scuttling around her house. Alan patted her hand across the table and said, 'Come on, let's look around the house and see if we can sort this out once and for all.'
They meticulously searched every room for something that might move - curtains blown by the draft from open windows, books teetering on the edge of shelves that might have fallen, flies that might have crashed into the sensors.
'Pretty punctual flies,' Kathy smirked, as Alan wandered around with a can of insect repellent in his hands.
'We're eliminating every possibility,' he told her, zapping a gnat the size of a pinhead that was circling the lightbulb in the spare bedroom.
They even checked the back of pictures to make sure they weren't slowly sliding down the walls, and stood at the kitchen window waving a tinned pilchard at next door's cat to see if it knew a secret way into their house. It didn't. The mystery remained.
When they eventually fell into bed that night, Alan dreamed about smashing the alarm to pieces with a lump hammer, and Kathy imagined emigrating to a uninhabited island where house alarms weren't needed.
With baited breath, they set the alarm before they left for work the next morning. Alan said he was certain that today would be the first day of peace and tranquillity, but Kathy wasn't convinced. She volunteered for overtime again.
As Alan turned into his road that evening, he almost cried out loud. The noise of the alarm as he approached his house was deafening, and the blue flashing light highlighted the crowd gathered outside his front door.
Preparing to do a three-point turn and drive away, Alan glanced in his rear-view mirror and saw Kathy's car coming up behind him. They pulled up outside their house together, and got out of their cars with their hands clasped over their ears.
'I'm sorry, I'm sorry,' Kathy yelled above the noise, as they pushed their way through the angry crowd.
'We'll get it sorted,' Alan promised. 'It will never disturb you again.'
They both fell awkwardly through the front door into the hallway. Alan accidentally stepped on Kathy's hand as she bent down to pick the letters up off the carpet, and Kathy turned and thumped him in the arm and he rushed to punch the deactivating numbers into the alarm. They, like their neighbours, simply couldn't take any more.
'Where's the lump hammer?' Alan growled.
'In the cupboard under the stairs,' Kathy said.
He stomped down the hallway, threw open the cupboard door and hauled out the hammer. He dragged it to the control box on the wall outside the kitchen door, lifted it high above his head, and started to swing the fatal blow.
'WAIT!' Kathy screamed.
The lump hammer completed its arc through the air, but Alan managed to swing it sideways at the last moment. It missed the box and thudded painfully into the side of his leg.
'It has to be done,' he hissed through gritted teeth, as he raised the hammer again. 'This alarm has to die.'
'I know what causes it,' Kathy cried.
The hammer fell against the side of Alan's leg again. 'You do?' he gasped with a wince of pain.
'Yes.' Kathy began to laugh. 'I know what sets the alarm off every single day except Sunday, when we don't go out. And even if we did go out, the alarm wouldn't go off. Not on Sunday.'
Alan looked confused, but Kathy was jumping up and down with glee, waving the letters in her hands. 'There's a note,' she said. 'It reads, PLEASE get your alarm fixed. It goes off every time I call.'
'Who's it from?' Alan asked.
Kathy looked up at the sensor that was positioned directly above the front door, and said, 'The postman.'
