Manuella is a young and rich heiress married to Jean-Pierre. The latter is the director of the company owned by his wife, who merely signs contracts and invoices. Manuella suffers from a trauma that dates back to adolescence, when she witnessed the rape and then the murder of her older sister Nathalie by a simple-minded man. A shock she never recovered, which leads regularly to depression, even violent crises requiring treatment that administers her husband through bites. In order to change his ideas, Jean-Pierre takes his wife to winter sports, in Haute-Savoie where he rented a chalet. He meets his mistress Françoise, accompanied by her Patrick, his friend, who is aware of the liaison of his girlfriend with Jean-Pierre. In fact, the latter, with the help of Françoise, plans to sink Manuella into irreversible madness, in order to seize his property.