Sherlock series 4: Episode 1 and 2 titles and what they might mean

Sherlock's characteristically quizzical air has left fans utterly in the dark when it comes to what may befall Benedict Cumberbatch's legendary detective.

The San Diego Comic-Con trailer saw Sherlock look uncharacteristically shaken, amidst a looming threat which may (or may not be) the return of Moriarty; meanwhile, the show's stars have teased the season to be the "darkest" of the entire series. 

A few morsels of information which will inevitably be poured over on the release of the first two episode titles of season 4; initially as part of UK fan event Sherlocked, before appearing on BBC One's Twitter feed.

Episode 1 will be titled “The Six Thatchers”, with Episode 2 coming with the equally mysterious, 'The Lying Detective'. Continuing with the show's consistent bowing to Arthur Conan Doyle's original tales; the titles appear to be based on the “The Adventure of the Six Napoleons” and “The Adventure of the Dying Detective”.

“Six Napoleons' sees Holmes investigate a murder connected to a series of mysterious breakages of busts of Napoleon, with the Thatcher part of the title presumably connecting to former prime minister Margaret Thatcher; other than that there's not much to uncover here. 

 “The Dying Detective”, however, sees Holmes convince Watson and co. that he's dying of a rare disease in order to entrap a certain Mr. Culverton Smith into confessing to his nephew's murder;Toby Jones has already been revealed to be playing Culverton Smith, meaning the episode will presumably see his introduction and follow some sort of spin on the classic tale.