Marie and Antoine live together. They are in love. She wants to have a baby, but he does not agree. She meets Paul. Paul tries to seduce her, Marie rejects him, but when Paul sleeps with her sister Juliette, she realizes she is in love with him. She tries to forget him with Antoine, but Antoine imagines they had sex and is very jealous. Marie is lost : she thinks of Paul when she is with Antoine and of Antoine when she is with Paul. She becomes pregnant and is not sure of who is the father...