Antoine Mongeville, a former investigating judge in Bordeaux, meets a Criminal Police detective who he will have to work with. Despite their tense relationship and their opposed characters, they will realize that they are not so different.

In 2016, French writer and photographer Carole Achache took her own life. After Carole's death, her daughter Mona Achache, a film director, discovers thousands of photos, letters and recordings that Carole left behind, but these buried secrets make her disappearance even more of an enigma. Through the power of filmmaking and the beauty of incarnation with the help of actress Marion Cotillard, the director brings her mother back to life to retrace her journey and find out who she really was.