Dr. Cordelier, living in a suburb of Paris, withdraws from society to pursue research into the functioning of the human brain. His lifelong friend, Maître Joly, becomes concerned when Cordelier draws up a will that bequeaths his entire estate to a stranger, Monsieur Opale; he cannot understand why Cordelier defends him, considering Opale attacks women and children. After a colleague is killed, Joly confronts Cordelier and discovers the truth behind his friend's behavior.
| Production | Jean Renoir | Producer |
| Writing | Robert Louis Stevenson | Novel |
| Writing | Jean Renoir | Screenplay |
| Camera | Georges Leclerc | Director of Photography |
| Directing | Jean Renoir | Director |
| Editing | Renée Lichtig | Editor |
| Sound | Joseph Kosma | Original Music Composer |
