Marcus Valerius Aquila has scarcely landed in Britannia when he has to run for his life - condemned to dishonorable death by power-crazed Emperor Commodus. The plan is to take a new name, serve in an obscure regiment on Hadrian's Wall and lie low until he can hope for justice. Then a rebel army sweeps down from the wastes north of the Wall, and Marcus has to prove he's hard enough to lead a century in the front line of a brutal, violent war.