The series begins in May 1940, a time when local Germans are being interned, the bombing of England has commenced, and anti-German feelings are running high. Detective Chief Superintendent Christopher Foyle's request for a service transfer is again denied, and he returns to local police work in Hastings. First broadcast in 2002 and covers the Spring/Summer of 1940.
May 1940. At a time when German nationals are being interned in British camps, the beautiful Austrian wife of a local magistrate is resented by the locals. When she is found murdered, a swastika painted on a nearby tree, Foyle realizes the seemingly peaceful Sussex town harbors any number of suspects.
May 1940. The arrest of a young girl on a sabotage charge brings Foyle into contact with a group of English Nazi sympathizers. Shots are fired at the group's charismatic leader, but it is the hotel owner who dies. Foyle investigates the murder and uncovers a plot to smuggle a vitally important letter to the enemy.
June 1940. A conscientious objector dies in police custody, setting in motion a series of suspicious deaths and a complicated puzzle for Foyle. When Foyle has pieced together the truth, the entry of Italy into the war engulfs a close friend in tragedy.
August 1940. In the course of investigating a murder, Foyle uncovers a plot to steal art treasures being moved from the local museum to Wales for safekeeping. Meanwhile, Foyle's son flies his first mission as a Royal Air Force pilot and is accused of passing top-secret information to the enemy.