Agathe is a mother who leads a peaceful life with her husband and two children in a stylish residential area. When she begins to doubt her husband's fidelity, she investigates his business trips and discovers a terrible secret.
Devastated by Fred's confession, Agathe decides to leave him. She discovers that her comfortable life is a golden cage from which it is difficult to escape. While Fred tries to earn her forgiveness, Agathe organizes discreetly her escape.
A year later, the start of the trial is making headlines in the press. What really happened that night? Who will be punished for their crimes? Who is the monster in this story?