The western provinces - Gaul, Spain and Britain - have been seized by the pretender Postumus. To the east, on the plains о northern Italy, the armies of the emperor Gallienus muster. War is coming. Everyone must choose a side. On a mission shrouded in secrecy and suspicion, Ballista must journey the Amber Road to the far north, to Hyperborea, back to his original home and the people of his birth. Along the way, Ballista meets a fearsome, masked warlord, who attacks, bringing fire and sword against Ballista and his men. And in Hyperborea, not all welcome Ballistas return. In the battle between Postumus and Gallienus only one can survive and be emperor.