On an isolated property in the middle of the French countryside, two women and a man share a simple, unadventurous and sometimes painful life. Clara, married to a man who is often away, with no children and no expectations, spends her days with Lili, her sister. But Lili is not like other people. One day, when she is particularly tired, Clara, who is usually patient and devoted to her sister, feels the urge to kill her. Totally distraught, she feels increasingly anxious at the idea of not being able to control herself.