Popaul Thomas returns after fifteen years in the army and assumes charge of his late father's butcher shop in the peaceful town of Tremolat. He begins courting Helene Marcoux, the local head-mistress, but she insists that their relationship remain a platonic one. The quiet life of Tremolat is interrupted by news of a brutal murder nearby, and an even greater disturbance follows the discovery of a young bride stabbed to death. Her body is found during a children's picnic into the country-side, and Helene finds beside it a cigarette lighter like the one she had given to Popaul for his birthday. She keeps her suspicions to herself and is relieved to see Popaul using his lighter when he visits her that evening. Yet a murderer is still on the loose ...