When the deputy commander of Rome's Imperial Security Service is assassinated on the island of Rhodes Cassius Corbulo swiftly finds himself embroiled in the investigation. Assisted once more by ex-gladiator bodyguard Indavara & servant Simo his search for the truth is complicated by the involvement of the dead man's headstrong daughter Annia. Braving hostile seas Cassius & his allies follow the assassin's trail south aboard a ship captained by a roguish Carthaginian smuggler & manned by his disparate dangerous crew. Their journey leads them to the farthest reaches of the empire; to a ruined city where the rules of Roman civilization have long been abandoned & a deadly battle of wits with a brutal relentless foe.