It is 33AD, and Breaca, the red-haired daughter of one of the high-born leaders of the Eceni tribe is on the cusp between girl and womanhood. She longs to be a Dreamer, a mystical leader who can foretell the future, but having killed the man who has attacked and killed her mother, she has proved herself a warrior.
Beside her is Ban, her half-brother, who longs to be a warrior, though he is manifestly a Dreamer, possibly the finest in his tribe's history. Having saved Caradoc, the future war-leader of his people, who has been shipwrecked on the Eceni shore, Breaca and her family travel to his father's court, where they are betrayed, and Ban is sold into slavery in Gaul. Believing Breaca to have been killed, Ban swears vengeance on Caradoc's tribe, then focuses on staying alive in an alien land where even to admit to being a Celtic Dreamer is to invite instant death.
Ten years later, Ban, whose skill as a horseman has enabled him to join the Roman cavalry, finds himself as part of the new emperor Claudius' invading army. Across the Medway, British forces face the Roman legions. At their head is Breaca, leader of both the Eceni tribe and the warriors of Mona, Britain's bravest fighters. Against her, a key member of Claudius' cavalry elite, is Ban, hatred burning in his heart, vengeance on his lips. Both are unaware of the other's existence. Both are prepared to fight to the death.