The exploits of Chief Police Inspector Chabrier, first before the invasion of France in May 1940 as he fights against spies preparing the coming the Germans, particularly Emmy de Welder, the alleged manager of the Rouen hospital. Later, Chabrier and his men go underground and resist the occupiers whatever the price to pay. When the Liberation comes Chabrier resumes his activities at the French National Police.

Le commissaire Chabrier tente de lutter contre des espions allemands en 1940. Il constitue ensuite un réseau clandestin contre l'occupant. Film en deux parties : "L'espionne" et "Réseau clandestin".