A young woman, Claude Alphand, runs an investigation agency. A landowner, Arnaud de Maule, hires her to uncover the perpetrators of threats he is receiving. Shortly afterward, Arnaud's mistress, a young actress named Chloé, falls under the sway of an esoteric religious sect. With the help of Florence, a radio producer, Claude frees Chloé, but discovers in the process that Arnaud is conducting dangerous experiments.