Foyle, now working for British Intelligence, is drawn into the world of corrupt Nazi businessmen when London university professor William Knowles is found brutally murdered in a London park. When it transpires that the professor was actually working at the Nuremberg trials, Foyle realizes that there are powerful people trying to conceal secrets from the war.

When a young student is badly assaulted, Foyle wonders if the attack is racially motivated as the young man was the son of a wealthy and high profile Jewish businessman. 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.

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.