Brussels, early 60's. Alice and Céline live in twin bourgeois houses. They are best friends as are their children, Theo and Maxime, who have grown up like brothers. Both families spend all their time together. This perfect harmony is broken when Maxime, Céline's son, tragically falls to his death from his bedroom window. This accident happens very quickly and Alice, witness of the scene, can't save him. Blinded by the pain, Céline blames Alice for not saving her son. Céline's behavior becomes more and more suspicious - Alice fears her friend is seeking revenge on her son Theo.