There are worlds, within worlds, within worlds.

Some worlds are defined by heartbreak. Some by fire, some by ice. Nearly all worlds follow a pattern of infrastructure, an idea, a person. A person can indeed change a world.

Yet, a man is not immortal. A man, barring radical changes in science or the discovery of powers higher than should be possible, will not outlive a century. A man can be so very ordinary...

… yet, a man can change everything.

In one world, it is defined by the meeting of two men. One brilliant, anti-social, genius of a man, a consulting detective who dances so very often upon the line of good and evil. A man who, while on the side of the angels, is not one of them. The other man, a former Army doctor with a taste for danger. A man who has walked with kings and yet remain true to his middle-class roots, who is nearly always wrapped up in jumpers and jeans and watches crap telly while, in a drawer somewhere, a rather illegal firearm sleeps.

They fight a criminal mastermind, the result of what the brilliant man could have been, and the ordinary doctor records these stories down. These stories immortalise Holmes and Watson, to do battle against the likes of Professor James Moriarty.

This is not that world.

Conjunctions form by providence. A meeting of two men in a laboratory at St Bartholomew's Hospital; one great but hardly good, one good but hardly great. Together, they are great and good.

Before that, there was a joke, a joke between an Irish student who is a genius, too, but pretending to be not, and another student, who is studying medicine, and then both of them are dreaming.

"What the hell can I do?" the Irishman was saying. "Acting, theatre, chemistry, mathematics! It's all boring!"

The student of medicine laughs, unaware of the malice hidden under a sharp nose and shifty reptilian eyes, or perhaps uncaring of such a feature. "I dunno, Jim. You could be a consultant. 'Dear Jim, I can't figure out Euler's equation, please help'. 'Dear Jim, I can't hit the high notes for the school's latest Wagnerian plot-'"

"Booooring, Johnny, booring..."

"'Dear Jim, please get rid of my sister's abusive wife for me'," the medical student chuckled. "You're a brilliant man, Jim, you can make it anywhere. Please don't try to become a serial killer, though."

The Irish student of multiple disciplines, for of course the intelligent could make it anywhere, freezes, turning onto the medical student with three names with sudden alacrity. "...'Dear Jim'?"

"Well, we write letters, they start out with 'Dear insert name here', Jim. You don't skip the salutation, that's just rude. You did write it in for your visa application, right?"

"That's... that's amazing. John, you're lovely and brilliant and I could marry you."

"I'll take your word for it."

Later, when the visa application fails and our students run to Gretna Green, and the signatures are made and rings exchanged, our students set out in life as Moriarty. One follows the path of a soldier, meeting his husband only on leaves and the repeating honeymoon that doesn't so much repeats as continues from where they leave off. The other becomes a consultant, a euphemistically titled 'solutions provider' whose only call-sign becomes the first totem that defined the bond: 'Dear Jim'.

Dr John Watson-Moriarty. Mr James Moriarty-Watson.

Moriarty.