Based on the novel by Tatiana de Rosnay, Emmanuelle Devos plays Diane, a distraught mother who walks out of an institution in Lausanne, Switzerland, to cross Lake Geneva to Evian, France in the hopes of finding the two people responsible for the hit-and-run accident that killed her son. After contacting a detective, using his circumstantial evidence, the sale of a Mercedes seen at the accident leads her to intercede into the lives of Marlene (Nathalie Baye) and her partner Michel. It’s the comparisons between these two women, both facing the weariness of middle age, that provides the challenge in director Frederic Mermoud’s suspense thriller about retribution and responsibilities.