What it says on the tin. (Including Follow-ups to: Maybe one of these days you can let the light in, and One Of Those Things, and Mrs and Mr Pond..)

“Eternity is really rather boring, John. Mortal life seemed as though it would be far more interesting.” Sherlock is actually the Devil, but he decided to live as a mortal because ruling Hell was boring.

The thing that made it so easy to hide was that everyone knew what dragons were supposed to be like. John heard people wonder about Sherlock sometimes, sending him slanting, speculative glances, as they questioned his lineage. But John Watson, who was steady, reliable, even-tempered? He slid right under their radar, just another average human being in a world full of them.

Sherlock has just run off in a whirlwind of coat without a word, leaving Scotland Yard cursing his name. It’ll be a while before they can get someone to translate this, and meanwhile that tall know-it-all bastard has gone off to do god-knows-what without bothering to even tell them what the note says. John edges forward in the middle of the uproar, and surreptitiously glances at the note. Androvy, it says briefly. The warehouse at five. Serdyukov. John seems like such an ordinary bloke. Appearances can be deceptive.

“My high school reunion is on,” John tells Molly. There’s a short pause as she processes this. “That sounds like fun,” she offers. “Do you want to go?” “Oh yes, because that couldn’t possibly go badly. ‘Hello, I’m John Watson, I’m a professional killer.’ ” A Grosse Pointe Blank AU.

And how things could have gone differently.

“Your first mistake,” John says smoothly, “was calling yourself Moriarty. It got my attention.” In which Jim is not, in fact, Moriarty.