The film story depicts Emile Buisson, following the death of his wife and child, escaping from a psychiatric institution in 1947 and returning to Paris. Buisson, who three years later would become France's public enemy number one, begins a murderous rampage through the French capital.

Alain Delonas Roger Borniche
Jean-Louis Trintignantas Émile Buisson
Claudine Augeras Catherine
Renato Salvatorias Mario Poncini
André Pousseas Jean-Baptiste Buisson
Marco Perrinas Vieuchene
Henri Guybetas Hidoine
Maurice Barrieras Rene Bollec
Denis Manuelas Lucien Darros
Maurice Biraudas Owner of the Saint-Appoline hotel