During the second year of their campaign against the British tribes, the Roman legions are under great pressure to complete their mission.

However, at a crucial juncture in battle, Macro and Cato's superior, Centurion Maximius, loses his nerve after discovering an auxiliary outpost had been massacred by British raiders and leads his cohort on a revenge mission, in spite of his orders to defend a vital river crossing.

Maximius gets his revenge, but is alerted to the danger of Macro's century and rushes back to the aid of his junior centurion.

Because of this failure to halt the escape of Caratacus' army, and the subsequent delay of Claudius' triumph at Rome, an inquest, overseen by General Plautius and Narcissus, leads to the decimation of the cohort.

Cato and his fellow convicts escape their punishment and are forced to wander the British countryside, looking for a safe place to hide from their enemies, both Roman and Briton.