A new civil war has begun: with the emperor Pertinax's murder Marcus and his protector Scaurus have escaped Rome, seeking sanctuary for their familia in the East.

But they are soon pressed back into service by Septimius Severus, the ruthless commander who has seized the imperial capital and who holds the military balance of power over his two rivals.

Niger, the would-be emperor in the East is on the march with six legions, and Scaurus's legion is ordered to Thrace as a sacrificial advance guard, tasked with delaying them. Whatever the cost....