In the middle of a wild rave party, the body of a 78-year-old man is discovered among the crowd, beaten and stabbed. There's no way to trace the identity of this elderly man. Darius and his colleagues are left in a state of incomprehension: what was he doing there? And why didn't anyone seem to have seen him during the party? While Marijo finds a strange piece of paper in the victim's jacket lining, we then discover Françoise, her husband, and their best friend. They're all between 75 and 84 years old. Their common thread: a general sense of fed-upness. Their pensions are ridiculous, they feel like they've become a burden on society, and they're slowly dying. Their plan? To rob a supermarket.