The war has now ended and Sam's new boss artist Sir Leonard Spencer-Jones is found murdered in his home. The main suspect is Niko, a Russian prisoner of war whom the artist had befriended. Niko finds sanctuary at Russian House in London. Foyle is assigned the task of bringing him back into custody. When Foyle and Sam arrive in London they investigate more.
Foyle finds himself going head to head with the US army as racial prejudice erupts. Mandy Dean is one of the residents staying at a guest house being run by Sam and Adam. She finds herself all alone disowned by her family as she has had a mixed-race baby. He ex boyfriend is hoping to get back together with her and after she is murdered the finger of suspicion points towards him.
Foyle learns when he can finally leave Hastings police station with his tenure as Detective Chief Superintendent over. When he reads a headline in a newspaper about a member of a distinguished family about to be hanged for treason he decides he has one last case to look at.