Sherlock season 4’s biggest mystery is here! Forget the cases, the murders, and guest stars. Who does the detective say ‘I love you’ to?

Season 4 of Sherlock will ring in the new year, but until then, here is another look at the darkest season yet. The big bad of the season, Toby Jones’ Culverton Smith, looms large over this sneak peek. We may not know what he’s up to, but Sherlock sure does.

‘Sherlock’ season 4 preview:

“You know why I’m here,” the detective tells Culverton. Sherlock’s always been one mile ahead of the game, but this, as the detective points out, is no game. One of the most surprising aspects of the trailer includes Sherlock uttering a certain three word phrase.

The words “I love you” are quite foreign to Sherlock’s lips. In the scene we see both Watson and Mycroft standing on either side of him. But who are the words directed at? Only time will tell!

Announced earlier, the finale will run in theaters on both Monday, January 16, 2017 and on Wednesday, January 18, 2017 both at 7:00 p.m. local time. Both of these airings will take place after the finale airs on television.

The BBC announcement states, “Audiences will experience laughter, tears, shocks and surprises in this thrilling, not-to-miss season finale.” The most exciting bit of the theater experience might be the inclusion of “15 minutes of exclusive extras.” That plus seeing Cumberbatch and Freeman on the big screen are worth the price of admission, right?

Who do you think Sherlock says ‘I love you’ to?

Sherlock season 4 premieres on BBC One in the U.K. and PBS in the U.S. on January 1, 2017.