Marcus Corvinus, Ancient Roman aristocrat, layabout and amateur detective, is holidaying by the sea at Baiae with his wife, mother and stepfather when the town drunk Trebbio is accused of the murder of local fish farmer Murena. Only thing is, Corvinus is sure Trebbio didn't do it. So he must find who did. Not easy, since the Murena Fan Club had a total membership of approximately none, particularly within the deceased's toxic family - a widow, daughter, two sons and a son-in-law are all firmly in the frame, and that's just for starters. But these problems pale into insignificance beside the fact that Corvinus's mild antiquarian stepfather Priscus has, rather late in the day, decided to let his hair down and go off the rails...