A businessman was stabbed during a round of golf. It is his daughter who discovers his corpse, one Sunday morning. The young woman is suspected by investigators because the day before, she had had a heated argument with her father, who accused her of frequenting a trendy nightclub, known to be the hub of drug trafficking. But Revel and Mélanie soon have another suspect, a certain Antoine Copeau, who is none other than Mélanie's former partner when she worked at Stups. Under a false identity, Antoine Copeau became the manager of the box as part of an undercover operation ...