Remember the good old days when Sherlock used to have light, funny moments, like scenes of its hero walking around Buckingham Palace wearing nothing but a bedsheet? Those days are in the past, as a new teaser for the fourth season of the show reminds us. “What’s the very worst thing you can do to your very best friends?” asks Toby Jones, playing the season’s Big Bad, as scenes of fiery infernos and stark interrogation rooms fly by. “Tell them your darkest secret.” This is followed by Holmes turning to the camera and declaring, “I love you.”
Wait, what? It’s downright bizarre to hear that phrase coming from Holmes, a self-described sociopath whose relationships range from mild, perplexed affection to barely tolerating other people’s presence. While it’s unlikely that this is any kind of romantic declaration, this is still a major revelation for his character. But who’s on the receiving end of this pronouncement? And why now? Here are some theories.
Molly Hooper. Poor Molly has harbored a crush on the often cold, distant Holmes for so long. Holmes has called her the one person “who mattered the most,” which is already pretty warm and fuzzy coming from him, so she’s probably not on the other side of that fourth wall.
James Moriarty. Is he dead? Is he alive? It’s difficult to tell these days. The last teaser we had for Season 4 suggested that Holmes’ greatest nemesis was definitely deceased but, confusingly, also up to some new mischief. Moriarty has always been the ultimate foil to Holmes, since the two are so similar. Maybe Holmes admitting his love for Moriarty, real or hallucinated, is an admission of love for himself.
John Watson. Sherlock has long been accused of queer-baiting, with one of the show’s running jokes being that other characters consistently mistake Holmes and Watson for a couple. For Holmes to outright declare any sort of romantic love for his longtime partner seems unlikely—and not just because Watson is standing behind him when he says. (It seems more likely that Holmes would be unable to face Watson while admitting his feelings.) Still, it could be a platonic admission of how much Watson means to Holmes and would be a significant step in his character development.
Mycroft Holmes. My money’s on this one. Mycroft, like Watson, is standing behind Holmes, but for the reasons discussed above, I don’t think that rules him out. What’s more, writers Steven Moffat and Mark Gatiss, who also plays Mycroft, have teased that this season will be downright “tragic” (because the last one was so cheery), which suggests a character will be killed off. Mycroft, with whom Sherlock’s relationship has always been complicated, would be a good one to kill off for some real emotional resonance.
You, the viewer. Holmes’ darkest secret could be that he has used his superhuman deductive reasoning to figure out that he is actually an actor named Benedict Cumberbatch, who is playing character on a television show. He loves you, the person watching Sherlock, because your continued viewership allows him to continue to get paid an ungodly sum of money with every new season.
Sherlock returns to PBS Masterpiece on Jan. 1, and the finale will air in theaters Jan. 16 and 18.