Stéphane Blanchon lives a quiet life in Switzerland with his wife, Christine, until a young American boarder named Belle, who was living with them, is found murdered. Despite Stéphane's innocence, the evidence points to him, and he learns that Belle harbored romantic feelings for him. Suspicions mount against him; even Christine thinks he is the culprit. Stéphane's sanity begins to crumble, and he lashes out in unprecedented ways.

Francois is engaged to Isabelle. While going to buy the engagement ring, he meets Sophie, who puts the ring on her finger and does not manage to remove it. Francois follows in the footsteps of Sophie, who is married to an important merchant, in order to recover his property.