Elisabeth is very protective of her teenage brother Paul, who has been injured in a snowball fight at school and has to rest in bed most of the time. The siblings are inseparable, living in the same room, fighting, playing secret games, and rarely leaving the house. Paul's friend, Gerard, often drops by to stay with them. One day Elisabeth brings home Agathe to live with them. She bears a strong resemblance to Dargelos, a schoolboy whom Paul had a crush on and the same boy who injured him. Paul and Agathe become attracted to each other, causing Elizabeth to be very jealous.