The long-awaited fourth season of “Sherlock” is almost here, set to premiere on New Year’s Day, and the first trailer for the long-awaited return of the Benedict Cumberbatch-starring drama hints that this may be the darkest season yet.

In the clip, Cumberbatch’s Sherlock Holmes and sleuthing partner John Watson (Martin Freeman) face off against a new villain, played by Toby Jones (“The Hunger Games”), who is said to be the duo’s most formidable foe to date.

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Even more intriguing, however, is how the teaser trailer ends, with Sherlock saying three words we never thought we’d hear him say: “I love you.”

The fourth season of “Sherlock” debuts on Sunday, Jan. 1.