John's a doctor. But when he's not a doctor, he's a werewolf.

A fourth episode, beginning where the third ended. In which Sherlock and John play the cards dealt to them; featuring running, puzzles, running, a card game analogy, and more running.

It certainly wasn't the first time he'd been woken up at ridiculous o'clock; it wasn't even the first time he'd been woken up at ridiculous o'clock in London, in the comfort of his own flat. But as John Watson's fingers closed reflexively over the handle of the bedside drawer, yanked, and then plunged inside to close around the familiar weight of his side arm, he realised that it was the first time he'd been woken up by Sherlock Holmes silhouetted on the threshold of his room, with a feather in his hair, snapping his fingers peremptorily and announcing: “Gun. Now.”