Impossible decisions are faced and sacrifices are made.

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

Taverner is desperate to hide dangerous secrets. River seeks answers at his grandfather's house.

River is trapped in France. Back at Slough House, the Dogs have come for Lamb.

A naive agent makes a discovery about the Westacres bomber. Lamb suspects that David knows more than he's letting on.

A London bombing puts Taverner under pressure. When River grows concerned for his grandfather, Louisa encourages him to go for a visit.