One evening, crime reporter Jacques Batissier makes the acquaintance of a drunk stranger who tells him his version of the murder of anti-fascist publisher Sonelli. When detective inspector Rochambeaux investigates the case, the portrayal of the unknown proves to be an exact description of the circumstances of the crime, which only the murderer could have known. On the hunt for a good story, Batissier gets on the trail of the powerful fascist secret organization "Cagoulard".