The second season of the BBC's Sherlock — which offers a modern retelling of Sir Arthur Conan Doyle's stories with Benedict Cumberbatch in the title role — ended with Sherlock Holmes jumping from the roof of St Bartholomew's Hospital. With that, the new trailer for the third season of Sherlock begins the only way it really can: With a shot of Sherlock Holmes' grave.

Of course, Sherlock Holmes isn't dead. For one thing, that would make for a pretty dull third season; for another, fans of Arthur Conan Doyle's original stories know that Holmes faked his death in the source material — and that didn't stop him from reemerging and solving more cases. But if Sherlock's return isn't a surprise for audiences, it's a surprise for the show's characters — particularly Watson, who moved on with his life in the wake of his friend and partner's death. "I don't care how you faked it," says Watson. "I want to know why."

We don't get Sherlock's answer in the trailer — but we do get a sense of why he came back. "The terror alert has been raised to critical," says Sherlock's brother Mycroft. "An attack is coming." Is this the latest case on Sherlock's docket, and will Watson be willing to abandon his new life to team up with the old friend who left him behind? U.K. viewers will find out when Sherlock premieres on BBC One on New Year's Day.