A postman in a small mountain village finds a woman and her son both dead in the "grotte aux loups" (cave of wolves). He soon begins to realize than it's not natural death, and that someone in the village in behind their murder, while tragic events occur.

Mika, heiress to a Swiss chocolate company, is married to celebrated pianist André and stepmother to his son, Guillaume, whose mother died in a car wreck on his tenth birthday. Their lives are interrupted by the unexpected arrival of Jeanne, a young woman who has learned she was almost switched with Guillaume at birth.

Madeleine, who runs a disco on the French-Swiss border, dreams of going to Paris to pursue a singing career. Her lover, Paul, who makes his living smuggling money, gold and goods across the border, plans to emigrate to Canada. Mali, a pretty young Algerian woman who lives in France and works in Switzerland, would like to be anywhere except where she is. Louis, born on a Swiss farm and trained as a clockmaker, would give anything to leave his mistress, Lucie, and move in with Mali.

Jean-Luc, mountain farmer, married Christine. She accepted this marriage because the man she loved, Augustin, left. Jean-Luc knows this but he hopes that the birth of a child will allow them to live together possible. Unfortunately, daily life between work in the fields and Sunday mass destroys their understanding. After Augustin's return, Christine becomes his mistress and Jean-Luc discovers it. He chases Christine away and remains alone with their child but the latter drowns shortly after in a pond. Refusing to believe in the death of his son, Jean-Luc descends into madness. When a few years later, he sees Christine again with Augustin's child, out of jealousy, he kills the mother and the child, before killing himself.