Roman Empire, 52 AD. Emperor Claudius, old and sick, is about to die. The emperor's son Britannicus and Claudius' stepson Nero are fighting for his throne. The main trump card in this struggle is the position in the new Roman colony of Britain. The only difference is that the heir’s supporters crave a final victory over the barbarians, while Nero’s supporters benefit from further instability across the strait. Therefore, Narcissus, the imperial secretary, gives the task to the prefect Cato and his faithful friend, the centurion Macro, to bring victory over the rebellious leader of the Britons as quickly as possible. At the same time, he informs them that the opposing party has sent its agent to the colony, who will strive to prevent the defeat of the barbarians. And this infiltrator must be stopped - at any cost...