Mention to anyone that you're the head of a large crime syndicate who gets paid to organise and perpetrate crime on a national and sometimes even global level and, chances are they will, more than likely, assume you have quite a thrilling job.

Not so. Jim Moriarty knows how erroneous that assumption is.

Which isn't to say that he doesn't enjoy his job, because he does, but sometimes, like any job, it can get a little boring. A little repetitive. Sometimes it can be very dull. The overwhelming majority of cases presented to him are boring and simple; things his clients could probably sort out themselves if they put a little effort into it. He turns most things down unless there is something he can gain from them: stimulation, contacts or sometimes, just sheer amusement at watching panic erupt among the public.

Moriarty isn't exactly sure how organising crime came to be his job; it was just something that happened gradually by chance or accident or a lucky stroke of fate. His first jobs seemed so exciting, and there was always the added risk of being caught because he didn't have the huge network of contacts he has today. It was all so thrilling and new; the gangs, the money, the drugs, the women, the challenge, the violence but it all got old so quickly. There's no challenge in it any more, nothing to stimulate him, and sometimes, in his darker days, Moriarty thinks of giving it all up. He doesn't give a shit about the petty rewards. He cares about the power and the intellectual stimulation; nothing else. But sometimes, the power alone isn't worth it.

And then it happens.

Something goes wrong. It's a small case, nothing too complex; a series of seemingly accidental deaths steadily wiping out the remaining members of what used to be a small secret society. Moriarty takes the job because it's been too long since London's seen a good spate of serial killings and, although none of the victims are obviously linked, they're all quite high profile people and the number of deaths spread across several months will create glorious panic across the country. Initially, the police seem baffled and, after the fourth murder, the arrest of some kid, a junkie, spreads victoriously throughout the papers. But after the fifth murder, something changes, and the police manage to arrest the real culprit, the man who hired Moriarty to do the job. He watches, stunned, and wonders how they figured it out. It must a fluke or something must've gone wrong.

A year and a half later, it happens again. The police manage to spot something wrong with the death of a rich businessman. Initially his wife and son are arrested, accused of killing the man so they could claim on his life insurance, but after a month Scotland Yard's finest arrest an associate with whom he had recently had an affair. Moriarty isn't behind this crime, but he was involved in facilitating it. Six months later, after the suspicious death of an employee, a small courier service is revealed to have links to a drug smuggling ring. Moriarty has nothing at all to do with that one, but recalling the events of six months and two years previous, his excitement grows. Is it possible that there's someone like him out there; someone who can actually use their brain; someone to play with?

Moriarty delves into the problem, spending hours finding copies of all the right files. At the end of it, he's found the one man involved in all three cases: Detective Sergeant Gregory Lestrade. Moriarty wonders briefly whether Lestrade could be his man, but there are other cases he's worked on that have been left open or solved incorrectly. It's happened too much to just be a fluke, but too little for Lestrade to be worthy of his attention. For possibly the first time in his life, Moriarty is stumped.

It's nine months before the Yard solves another tricky case; what seems to be a case of open-and-shut domestic murder is actually part of a new wave of discreet serial killings, as sponsored by Moriarty. But this time it's not Lestrade who makes the breakthrough - he's working on another case - but a Detective Sergeant Tobias Gregson. A few months after, Eric Hudson, one of his oldest and closest associates, is sentenced to death in Florida. Both Lestrade and Gregson were working on Hudson's case in the UK.

Desperate to know how they're solving the cases, Moriarty renews his investigations with more vigour. He pulls up all the files once more, and pores over them. Re-reading the Yard's notes about the drugs smuggling ring, he finds a statement, saying the Yard were assisted in their investigations by one Sherlock Holmes. A similar statement appears again for the serial killings and for Eric Hudson. Sherlock Holmes. It's a name he vaguely recognises, but is having a hard time placing. He decides to re-read all the case files again, and it isn't long before he finds the name again. It's in the first file; Sherlock Holmes is the mistakenly arrested junkie. Sherlock Holmes must've figured it out, must've mentioned something to Lestrade and must've been right, must've been the one to solve the case. And all the other cases since.

Moriarty finds out all he can about Sherlock Holmes. There isn't much. Upper-middle class upbringing, of course; attended prep school, private school and then Cambridge; arrested once for the illegal possession of cocaine and morphine and has been to rehab three times. In the past two years, he seems to have calmed down to the extent that the police are willing to ask for and acknowledge his help on some cases, which suggests that he must be good. Very good. Exceptional, maybe.

Moriarty smiles. This, he thinks, could be what he's been waiting for his whole life; a challenge that won't go away.

Two years later, he meets with Jeff Hope, although it's not the first time he's heard from the London cabbie. It's been a very long time since Moriarty has met one of his clients in person, but Jeff's proposal is very interesting and Moriarty has another intention for Jeff's work.

He tells Jeff they're going play his little game together - without the real pills, of course - and smiles gleefully as Jeff explains the rules and makes his move. Surprisingly, it takes Moriarty a moment or two to work it out, but he gets it right. Jeff, although slightly awestruck, isn't surprised that he's beaten and listens attentively as Moriarty outlines the details of the plan. He and his men will manufacture and send the pills to Jeff. Jeff will continue to do his job as normal and will only kill when instructed to do so. Thirdly, and most importantly, should Sherlock Holmes get involved with the case, he will be Jeff's next victim.

Moriarty has been watching Sherlock for a while now and, although one doesn't need to watch him in action to appreciate just how clever he is, Moriarty needs to know for certain. He has something planned, something fun for the two of them to do together, but he needs empirical proof that Sherlock is the man he's looking for, that Sherlock will play along, that Sherlock is as bored and intellectually alone as he is. Until he knows for certain, he'll have to restrain himself. Until he knows for certain, his plans cannot truly come into action. But when he does, when he knows, it's game on and, maybe, for once, being the head of a large crime syndicate will be just as exciting as most people assume.