It's up to the Slow Horses to stop Farouk's team from completing its mission in a final act of mass carnage.

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

Impossible decisions are faced and sacrifices are made.

Lamb and Katinsky go head-to-head. Ho finds himself trapped on a train with a Russian assassin.

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

Lamb questions David about France as River comes face to face with the enemy.

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

Lamb debriefs River and Coe. Roddy is pulled in to help decipher a piece of code as the destabilization strategy nears its final stage.

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

River Cartwright is ousted from MI5 and finds himself in a place worse than purgatory: Slough House, dumping ground for failed spies.

River and Sid join forces. A misfired gun has dire consequences.

Lamb liaises with a Russian defector who may hold a clue to sleeper agents. River is on the trail of a ruthless assassin.

Jackson Lamb is on high alert after a former spy is found dead. Min and Louisa are tempted by an offer from outside Slough House.

Taverner sends the Dogs to hunt down Lamb and the Slow Horses. River holds the secret to saving the gang.

A mass shooting rocks London, intensifying a testy mayoral race. Shirley believes one of the Slow Horses was the target of an attempted hit.

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

Lamb intercepts an assassin. Taverner receives a key piece of intel about the Abbotsfield shooting.

River gets cozy in the Cotswolds while searching for a sleeper agent. Min discovers Russian drinking games are the most brutal of all.