June 1941. Jack Archer works in bomb disposal. He is engaged to Gwen, daughter of the desk sergeant at the police department. One night, the stress gets to him. Drinking at the bar, he pulls a gun and almost shoot someone. Sam steps in and talks him out of his weapon.
Supplies are being stolen and sold on the black market. This affects the war effort when equipment cannot be repaired. Sgt. Milner is sent to work undercover. A man named Ian Kimble contacts him and says he can help get him supplies. When Paul goes to collect the goods, he and the police place Kimble under arrest. Ian pulls out a gun, shoots Paul and escapes.
In the meantime, Christopher is sent by his boss, Commissioner Rose, to keep an eye on Raymond Carter and his fiancee. Foyle is ordered to put all else aside to deal with this case. Carter is a known communist and may be causing trouble. As usual, nothing is as it seems and there is a surprising twist.
Foyle goes to the shipyard where Kimble works to ask questions. While there, there is an air raid. The factory is hit by a bomb, but it does not go off. The bomb squad comes. While in the warehouse, the three men find thousands of pounds of hidden cash. They manage to disarm the bomb, then stuff it with the money and take it away with them.
Added to the mix is Gwen trying to plan a wedding with the rationing during wartime.
There is a murder. Who did it? What happened to the money? How are all of these things related? Only DCS Foyle can seamlessly put all the pieces together that reveal the truth.