The date is 400 BC. Britain is a patchwork of tribes and kingdoms, united half a century ago by Dumnoualos of Dumnonia, whose armies brought peace to a land torn apart by war. But now the High King is dead, and he leaves two sons, Brennos and Belinos, who are both supported by rival tribal factions. Regardless of their own wishes, one of the brothers is destined to be High King, the other to be banished. And yet his deeds in exile will resound down the centuries, when the savage Celtic tribes burst down from the Alps to sack the nascent city-state of Rome.