'Sherlock' season 4 air date news, spoilers: Sherlock season 4 finale to hit U.S. theaters in mid-January

"Sherlock" is coming back in 2017 with three more cases to baffle its viewers' minds, while American fans will be in for a special treat in mid-January.

In the premiere episode of season 4 titled "The Six Thatchers," there is someone seemingly hell-bent on destroying every existing image of the late Prime Minister Margaret Thatcher. This rather trivial detail is what will catch Sherlock's (Benedict Cumberbatch) interest the most in a mysterious case that's baffling everyone else at Scotland Yard.

What could the destroyed Thatcher images mean? Could there possibly be a madman on the loose that's all set on terrorizing London for his own secret agenda? Or could the images represent something else with a much darker purpose; something that could potentially involve his friend's wife Mary (Amanda Abbington) and her past? What would this possibility do to the mercurial detective's friendship with Dr. Watson (Martin Freeman), especially now that the Watsons are about to become parents for the very first time?

Sherlock will also lay in wait for Moriarty's (Andrew Scott) posthumous retaliation. Will his arch nemesis continue to invade his mind palace or will the presumed dead criminal show himself in a different, perhaps more real way?

The trailer for the upcoming season show the tight pinch that Sherlock will be in as he struggles with his inner demons while he also tries to deal with every life with the people he cares about.

The final episode titled "Sherlock: The Final Problem" will also be shown in 350 theaters across the United States after it debuts on TV on Jan. 15. The theatrical showing will be presented by BBC Worldwide North America and Fathom Events on Monday, Jan. 16, and Wednesday, Jan. 18, at 7 p.m. EST local time. Aside from the full final episode, the theatrical release will also exclusively feature 15 minutes of extras.

"Sherlock" season 4 will premiere on Sunday, Jan. 1, at 9 p.m. EST on Masterpiece on PBS.