The body of fisherwoman Marie-Anne Pellat is found on the beach. She apparently fell off her fishing boat by accident, but coroner Marvaud confirms murder as cause of death and her missing boat must be located as crime scene. The brigade discovers that financial problems haunted her and several suspects, including her husband Daniel, are investigated. When the ship appears on high seas, the initial investigations point to a fight for controlling the smuggling of bluefin tuna.
