A quiet morning at Baker Street is thrown into turmoil by the arrival of Inspector Lestrade who informs Holmes a man's body has been discovered in the Tower Bridge which was then under construction. That grisly event proves to be the opening salvo in a terrifying game of wits between Holmes and an unknown adversary.

Determined to make Sherlock Holmes suffer, the ruthless foe launches a campaign of terror against the Great Detective. However, instead of striking at Holmes directly, this nemesis targets those in the Great Detective's limited circle of friends and acquaintances.

Stymied, Holmes must first ascertain why he has been targeted because he cannot retaliate until he discovers who is behind this persecution.

With moves and countermoves, gambits declined and accepted, the struggle soon evolves into a human chess game between Holmes and a grandmaster of evil - where each move might have untold consequences on the lives and reputations of those on both sides.