The Roman Empire's hold on the province of Britannia is fragile. The tribes implacably opposed to Rome have grown cunning in their attacks on the legions. Even amongst those who have sworn loyalty, dissent simmers. In distant Rome, Nero is blind to the danger.

As hostilities create mayhem in the west, Governor Gaius Suetonius Paulinus gathers a vast army, with Prefect Cato in command. A hero of countless battles, Cato wants his loyal comrade Centurion Macro by his side. But the Governor leaves Macro behind, in charge of the veteran reserves in Camulodunum. Suetonius dismisses concerns that the poorly fortified colony will be vulnerable to attack when only a skeleton force remains.

With the military distracted, slow-burning anger amongst the tribespeople bursts into flames. The king of the Iceni is dead and a proud kingdom is set for plundering and annexation. But the widow is Queen Boudica, a woman with a warrior's heart. If Boudica calls for death to the emperor, a bloodbath will follow.

Macro and Cato each face deadly battles against enemies who would rather die than succumb to Roman rule. The future of Britannia hangs in the balance.