Watch Masterpiece Online - Full Episodes

Sherlock's arch-nemesis, the criminal mastermind Moriarty, steps into the spotlight with a menacing vow and a cat-and-mouse game conceived entirely for the object of his obsession.

Sherlock and Watson investigate the Baskerville Experiments, rumors of top-secret government research on genetically engineered gigantic animals for military use.

A clever dominatrix tries to manipulate Sherlock at his own game.

Stephen continues to focus on his drawings, his deck of cards, and his one true love, despite the devastation surrounding him.