The body of Justine Delgado, a young girl of twenty, is found on a forest path. The victim, who died of internal bleeding, was kicked and kicked. Everything seems to blame twenty-one-year-old Ryan Kowalsky, a childhood friend of the girl. The latter, however, proclaims his innocence. François Delgado, Justine's father, is a police officer at the SRPJ in Lyon. Convinced that Ryan is the murderer of his daughter, he finds himself opposed to his own mother, Mireille Delgado, who she is convinced of Ryan's innocence. This dark affair is an opportunity for François and Mireille to settle old family accounts. Between the mother, a radical left activist, ready to launch an assault on all injustices, and the police son, insensitive to social issues and stuck in professional compromises, the disagreement quickly takes on the appearance of open conflict.