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.

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.