Marina and her boyfriend have an argument while on a trip in France. While driving with the car among the cliffs, he starts speeding and the car falls into the sea. Marina can jump out of the car, but her boyfriend seems to be drowned. She gets to know his brother and he falls in love with her. But why does she always feel watched? What reasons are behind her strange behaviour anyway? Did she really murder her boyfriend? But is he dead anyway?
In the train that takes her back home, Catheine Beryl meets concert pianist André Fuger, a childhood friend of her husband's. The musician is both good-looking and seductive and Catherine soon falls for his charms. The two young people spend the evening and the following night together. The next day, a lost powder compact gives the affair away. At a loss, Catherine runs away from her husband but she has an accident. When she regains consciousness in her hospital bed, Catherine finds Georges, her husband, by her side, pretending nothing has happened.
A stranger named Constant disrupts the life of Flora, who is seemingly happy with her husband Lucien. But she suddenly experiences a passionate love, taking refuge with Constant in a cave they call “home under the sea.”
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The Marquis de Montauran was appointed to command the Chouans whose first two revolts were crushed. An aristocrat, Marie-Nathalie de Verneuil, is sent by Joseph Fouché to seduce and capture him.
