One evening, crime reporter Jaques Batissier makes the acquaintance of a drunken stranger who tells him his version of the murder of the anti-fascist publisher Sonelli. When Detective Inspector Rochambeaux investigates the case, the stranger's account turns out 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".