Charles-Edmond, the eldest of the Larmentiel brothers, decides to return to La Rochelle, his hometown to die there. Forty years earlier he had been driven out by his father. Before passing away, the old eccentric announces that he has a hidden son, Émile, a fisherman to whom he wishes to bequeath his property. François, the younger brother, whom Charles-Edmond hates, is eyeing the inheritance to bail out the powerful family business, a veritable fishing trust, and will try to appropriate the affection and property of this inopportune heir. Émile, meanwhile, is too busy arguing with Fernande, a beugland singer, to suspect what awaits him...