The German wife of a rich and influential aristocrat exempted from wartime internment is found decapitated in the midst of anti-German feeling.

Foyle investigates a man found with a knife in his stomach in a bombed out building while son Andrew gets involved in a top secret radar program.

Sam volunteers to go undercover to discover how rationed gasoline is being stolen from a fuel depot, and Andrew becomes a suspect in a murder case.

Foyle's investigation of the death of a young black marketeer and stolen food is interrupted by his suspension on charges of sedition.

February 1941: When a local manor house is commandeered for use as a special burn unit for treating injured RAF pilots, Foyle is called in to investigate a series of strange accidents.