Later that day…..

“Mr. Holmes, Dr. Watson? There’s someone who wants to see you.”
“So, would you please let the Professor in.”, Holmes said, not even looking up from his evening reading matter, “I think it’s a rather urgent case.” 
As Mrs Hudson went out the door again, Watson looked somewhat puzzled at his friend:
“Holmes, I think I misheard here. Did you say ‘The Professor’?”
“Yes, Watson. I’m talking about Moriarty.”
“But how can you be so calm then?! And especially, how do you know that it is he?”
“This time it is too easy to explain. Mrs Hudson was somewhat confused. She referred to the visitor as ‘someone’. Normally she would had said ‘a man’ or ‘a client’ or ‘a Mr WhatDoIKnow’, but she would never had just said ‘someone’. And then the look in her eyes told me, that she was searching for a reason, why especially this person should come here. That means that it was a person, whom she knows, but it was neither one of our friends from Scotland Yard nor a client from one of our earlier cases. And it also wasn’t one of her friends, obviously. So there are just three persons left. The fact, that I neither saw Todd nor Smiley in the city, something what can be done at least once a day, tells me, that something happened to one of them; Something that confused the Professor that much, that he got to come here.”

Seconds later the Professor entered the room.
“Now, Professor, what instance brings you from Scotland to here of all places, pray tell ?”
“How do you know that I was in Scotland?”
“Pure and simple observation. It’s about 7 o’clock in the evening but it is obviously that you haven’t ate breakfast yet. You’d started this morning from Scotland and arrived in London a few hours ago and had to hide so as not to get caught by the Police. I would say you were visiting your elder brother at the old family mansion and you were in a hurry as you left”
“Yes,...How?!”
“Your jacket. The letters on the pocket are J.W.M., but your initials are J.R.M. for James Robert Moriarty, if I’m not mistaken. What we see here is the coat of James William Moriarty, your eldest brother. You were obviously in a hurry, otherwise you won’t have picked his jacket instead of yours. So, what happened in Scotland?”
Holmes looked his nemesis, curiously up and down.
“It’s ... it’s Smiley. He’s going to die. He’s very ill. We first thought that it was caused by the rain in the last week, but suddenly his state has become much worse, I think that there could be just one possible solution: Someone had poisoned the poor fellow.”
“The look on your face tells me, that you’re not telling a lie. But isn’t this something you could manage yourself?”
“I... I don’t think so. In fact, I already know the person who done it.”
“So, why do you need my help?”
“Because...”, Moriarty swallowed, “because, although I saw him in the village near the mansion a few days ago, it’s impossible that HE did it.”
“And why?”
“You see, Quentin Donovan, my suspect, is dead. For Sixteen years now.”
“Are you absolutely certain? Maybe he isn’t dead.”
“He is dead!”, Moriarty was on the verge of tears, “I know it! I... I killed him.”
“What?!” Holmes and Watson looked up confused.
“Yes. It’s a long story. But may I tell it to you on the way to Scotland? It actually is an urgent matter! What if this guy really is still alive? I’ve got no idea of how he could be able to poison Smiley, without us noticing it. I hoped you might know how.”
“Why should I?” Holmes blinked.
“I must confess, I read The Dying Detective, and I thought maybe you know a way after all what happened in that case.” Moriarty blushed slightly, with embarrassment.
Holmes chuckled briefly: “OK. I’ll help you. I think we should start right now, so that we arrive sometime tonight.

About an hour later the trio was sitting on their train to Scotland. They hadn’t talked since the train left the station. But now it was time to know something more.
“So, what is this “story” behind you, Smiley and this Donovan?” Holmes started, as he felt that they had looked out of the window long enough.
“Well, where should I start?”, Moriarty sighed, “ Maybe I first should tell you that I already met Smiley a long time ago… before he came back from India.”
“Really?!”
“Yes. I’m sure you know that I gained a professorship at a small university, and during that time I wanted to spend a holiday in Edinburgh. One day I came to a small house where I saw the following scene:
A young married couple was standing with their two children outside the house, ‘fighting’ against a,.. I would say, rich looking man, who was probably about 30 years old. As soon as I was close enough to them I heard the following…..
”Mr Donovan’, the poorer man shouted, ‘That’s nonsense! We can’t pay dat much money! ‘ow can ya say we got t’ get out out’ta ‘ouse?”
“Because the house still belongs to me, Marrow! And I’ll make the decision as regards, when or how much rent my tenants have to pay, and I have decided that you should pay more from now on, so either you give the money to me or…….!”
“But Mr. Donovan!’, the young woman cried, “We don’t ‘ave the money. My ‘usband an’ I are just poor workers, an’ our children are too young for work.”
“Tsk!”, sneered the landlord, “You know, your boy and that what he will offer me will be enough!” 
I was shocked as I heard that, and as that man grabbed the arm of the little boy, I jumped up, ran to the group and started to beat that guy. As his henchman tried to attack me, the father of the boy helped me with the two. Finally those guys ran away.
“I dunno ‘ow I shall thank ya, Sir. If ya weren’t ‘ere t’ ‘elp, I dunno what would ‘ad ‘appened.” the young man started.
“It’s okay. Who were those idiots?”
“Our landlord, Quentin Donovan. ‘e’s terrorisin’ me an’ ma family, but I can’t tell ya da reasons. ‘es a devil, y’ see.”
“Obviously!…Anyway. Allow me to introduce myself. My name is James Moriarty, I’m one of the Professors at the university a few miles from Middleton. May I ask who are you?”
“Aye. Ma name is Jake Marrow. Da beautiful lady there is ma wife, Fiona. And that are our children. Da lil’ gal with da doll is Evelyn. An’ this is our son. Say ‘ello, Smiley!”
“’ello there, Sir!” The little boy in the scruffy pants looked up to me and saluted. I bend down to him, grinning. 
“Hey little fellow, there is no need that you give a salute. Your name is Smiley, right?”
He nodded.
“Cute.”, I grinned, then I turned back to his father, “Don’t you have any relatives who could offer you a saver home, Mr Marrow?”
“Nay. Not a single soul with da name Marrow, neither in Britain nor in Ireland nor on da continent.”
“That’s a problem. You’ve got to get away from that Donovan chap.”, I thought for a while, “I think I got an idea. My elder brother lives on our old family-estate at the moment. I think you can stay there for a while, and maybe I can give your children a bit of an education.”

Firstly, Mr Marrow looked at me in surprise and bewilderment, then at his wife, and they both began to smile.

“Guddu hefju back, Sahib.” the Indian greeted the Professor.
“Thank you, Pitri. How is my boy?”
“Not gud, Sahib, not gud.”
The Professor just shook his head nervously, as they got into the carriage.