Bernard and Arlette Coudray live with their young son Thomas in an idyllic village near Grenoble. When the couple Philippe and Mathilde Bauchard move into the long vacant house next door, Bernard is confronted with his past. He recognizes Mathilde as his former lover. Their relationship, as passionate as it was conflictual, ended many years ago, but they still carry the wounds of their time together.
Their renewed encounter is not without consequences. Bernard initially tries to avoid Mathilde, but after a chance meeting in the supermarket they kiss and resume their affair. Unnoticed by their unsuspecting spouses, to whom they have kept their previous acquaintance secret, the two begin to meet regularly in a hotel. The outwardly neighborly friendship between the couples runs counter to the growth of obsessive passion.
In fact, at a garden party, emotions erupt when Bernard begins to attack Mathilde in a fit of rage. The two separate once more and yet fail to avoid each other - with disastrous consequences ... The finality of this obsession is underlined by the use of a narrator, Madame Jouve, owner of the local tennis club, whose accounts frame the story.
The sober, calm camera and touches of Hitchcock suspense also contribute to the film's claustrophobic mood.