A village mob is in pursuit of an arsonist. Fleeing from their hysteria, a seventeen year-old boy stumbles into a country house. He finds its owners, Jacques and Catherine, leading lives of monotony and habit. Jacques is a painter who divides his time between his canvasses and painting lessons he gives to the mentally ill in a nearby institution. Catherine is ill at ease in her arid, almost hostile surroundings, nurturing some unspecified dissatisfaction.
The boy Etienne - touching, bewildered - makes a deep impression on Jacques and Catherine. As a foil to their ennui, he is tormented, anxious, devious.His need for understanding and affection is persuasive; they take him in. Before long, he has insinuated himself into their favour and their home.
Etienne is a mass of contradictions. At once selfish and disinterested, he wants both to be of service and to extort the emotional support he needs. The strange menage take shape - Etienne has adopted Jacques and Catherine as his parents.