Nino Pastrengo, owner of a carnival float company, is found dead in his hangar inside the Viareggio Carnival complex. Initially, it's thought to be an unfortunate accident, then a murder orchestrated by a rival company. But was that really the case?

Mimmo investigates the case of Serena, who was involved in a car accident while returning home from a night shift at a private clinic where she worked as a nurse. But there were no skid marks on the road, and she hadn't consumed alcohol or drugs. Dodaro then decides to investigate the workplace.