Two great friends who practice cycling, Commissioner Servolle and real estate developer Faguet, see their friendship tested by the investigation carried out following the murder of Faguet's wife.
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.