For Alan, the thrill (as if there's one, as if the evening can withstand only that solitary frisson) is in Mycroft's treating, suddenly, the world outside his library as something more than mere inconvenience. It's in arriving, with Mycroft's vaguely maniacal punctuality, at a party of all places, and in the illusive luster the word “date” (a word he's danced not around but with, as assiduous a two-step as ever there was) casts over the excursion.

Which isn't to say the woman of the hour's appearance doesn't inspire a certain anticipatory excitement; nor is it to say Alan shies from flattery at the ever-capable hands of an expert. He breaks off smiling to adopt, fleetingly, an expression of mock-chagrin at his fully clothed state, and goes on to watch, with a blend of interest and undisguised amusement that's the closest he'll come to approval, something pass between his two companions.

"It removed the temptation to play with me on the way over,” he says, his innocence false and raffish as a gold tooth. He looks—in the event there was any doubt—unspeakably pleased with himself.