Slough House is the unlikely venue for a secret romance, but events take a dark turn when a dangerous encounter becomes deadly.

Taverner and the Slow Horses attempt different approaches to locate the kidnappers and Hassan. Ho makes a shocking discovery about Sid.

River has to steal something out of the Park to save a life. Lamb realizes a stranger game is afoot.

Marcus and Shirley face Lamb's wrath. River discovers revenge is a dish best served cold.

Tearney makes a bold move. The Slow Horses assist the Tiger Team, unaware of their hidden agenda. Lamb and Ho take a road trip.

Taverner and Tearney face off for control of MI5. River and Louisa find themselves caught in the crossfire.

The Slow Horses fight for their lives. Lamb shares some devastating truths with Catherine.