The snakes Henri Vidal meets in the big city (Paris) are much more dangerous than the reptiles he traps in the provinces. Outrageous plot twists, barely "coded" characters (Jean Tissier, Maria Mauban) who "befriend" him for nefarious purposes turn the tables on Vidal to the point where he's no longer the predator, but the prey. Nineteen-year-old, notably baby-faced Françoise Arnoul plays Vidal's long-suffering girlfriend, who's powerless to dispel the dark turn of events.