In the fiercely contested province of Britannia, the fate of the Roman Empire hangs in the balance: the fearless rebel leader Boudica is rallying more and more tribal warriors behind her as she sets out to conquer Londinium. Prefect Cato is tasked with the mission of defending the city at all costs. As he gathers the legions around him, he must do without his best man, Macro, who has been missing since the bloody battle of Camulodunum. In his darkest hour, Cato must ask himself: who can he still trust, and who is willing to fight by his side until the bitter end?.