Obsessed by the solar religions of the east, the emperor Aurelian sets out to obtain every sacred object within his realm. But one—a mysterious rock said to channel the power of the sun god—lies beyond his reach. Warrior-priest Ilaha has captured the legendary stone and is using it to raise an army against Rome. For Imperial agent Cassius Corbulo and ex-gladiator bodyguard Indavara, stopping him constitutes their greatest challenge yet. And when they finally reach Ilaha's mountain fortress, they face thousands of warriors who will give their lives to protect him...and the black stone.