Foyle finds himself being drawn into the strange murder of an ex-Nazi defector and leading expert on Soviet intelligence who had been working for MI5. Sam’s husband, Adam, is pre-occupied with his new political jobleaving her concerned that she’ll be able to share some huge news with him.

August 1945. DCS Foyle is replaced and is free at last - he's resigned his position and planning to travel to the United States for an extended tour. Before departing however, he's asked to look into the case of James Devereaux, a young man who joined the Nazi British Free Corps during the war.

July 1945. Sam moves in with Adam Wainwright to help run his guest house though, due to his shyness, they are not a couple. One of the tenants, Mandy Dean, is having a tough time, raising a baby fathered by black G.I. Gabe Kelly. Her old boyfriend Tommy Duggan is devastated when he returns and makes the discovery.

When his colleague Hilda Pierce is nearly killed in an attempted assassination, Foyle must re-examine her top secret role during the war to find out if there was a traitor at the heart of the Special Operations Executive.

Tasked with ensuring security at a high level Palestinian conference, with signs that a plot to bomb the conference maybe under way, Foyle faces a race against time to uncover not only the truth, but where the truth lies. Meanwhile Sam is determined to help a young boy in Adam’s constituency when she realises his life may be in danger because he cannot afford hospital care.

American troops arrive in Britain and the Corps of Engineers building an airstrip on a Hastings farm is met with resentment.

May 1945. Foyle joins a municipal committee that's preparing for the now imminent V-E Day celebration but soon finds himself investigating the deaths of two of its members.

After Foyle is a guest at a friend's home at a dinner for an important American diplomat, a suicide victim and German agent both are discovered near the house.

Foyle has his hands full dealing with illegal gambling, sabotage, and his needy goddaughter who shows up on his doorstep with her traumatized son.

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 the death of a Russian and it ends up leading to a mysterious military facility run by a Colonel with an impeccable war record.

Foyle investigates the suicide of a pacifist and death threats to the judge who ruled against his conscientious objector status.

Foyle is now working in a different new role working for British Secret Intelligence. As the iron curtain falls across Europe, MI5 believe that British atomic research has been infiltrated, and ask Foyle to investigate whether a Russian spy network could be at work in London.

October 1944. Foyle hones in on two murders: an unpopular psychiatrist in a trauma facility and a low security German POW on work release to a local farm.

A.C. Rose orders Foyle to delegate his investigation of black marketing ring and personally look into the possibly seditious acts of a Socialist activist.

With the English army trapped in France and a German invasion imminent, a Nazi sympathizer is murdered during a pro-Facist meeting at a country hotel.