On a small estate just outside Rome in the first century BC, two boys become blood brothers, little imagining the extraordinary future that lies before them. As friends and rivals, Gaius and Marcus are destined to find lasting fame.

Romulus and Fabiola are twins, born into slavery after their mother is raped by a drunken nobleman on his way home from a good night out. At 13 years old, they and their mother are sold: Romulus to gladiator school, Fabiola into prostitution, where she will catch the eye of one of the most powerful men in Rome, and their mother into obscurity and death in the salt mines. Tarquinius is an Etruscan, a warrior and soothsayer, born enemy of Rome, but doomed to fight for the Republic in the Forgotten Legion.

The Romans invaded Britannia in AD 43 confident of victory. They swept through a divided and ill-equipped enemy, scattered across tough terrain. But one man was not prepared to surrender. Caratacus - quick-witted youngest son of a a tribal king - had been trained from birth to be a warrior of power and grit. Sent to be schooled by the Druids in his boyhood, his training meant that an already strong and cunning prince returned to his father's kingdom as a war machine.

1179. Henry II is King of England, Wales, Ireland, Normandy, Brittany and Aquitaine. The House of Plantagenet reigns supreme. But there is unrest in Henry's house. Not for the first time, his family talks of rebellion. Ferdia - an Irish nobleman taken captive during the conquest of his homeland - saves the life of Richard, the king's son. In reward for his bravery, he is made squire to Richard, who is already a renowned warrior. Crossing the English Channel, the two are plunged into a campaign to crush rebels in Aquitaine.

The Roman grip on Britain is weakening. Emperor Nero has turned his face away from this far-flung outpost. The Druids are on the rise, spreading seeds of rebellion among the British tribes. Roman cruelty and exploitation has angered their British subjects. The warrior queen Boudicca will lead the tribes to war. Standing against the rising tide of Boudicca's rebellion is Roman Tribune, Gaius Valerius Verrens, Commander of the veteran legions at Colonia.