Anatolia, AD 260 The city of Edessa, a Roman outpost, is on its last legs after the Persian siege by the troops of Shapur I Emperor Publius Licinius Valerianus agrees to meet his adversary to negotiate peace But the meeting is a trap and Valerianus ends up in enemy hands, along with the commander of his personal guard, Marcus Metellus Aquila and ten of his most trusted men They are destined to spend the rest of their lives in slavery until Metellus and his men break free and find shelter at an oasis where they meet a mysterious exiled prince The Romans become his private militia and travel with him to his homeland, the mythical Kingdom of Silk - China And so they begin an epic journey to the heart of China, where the very survival of the world's two greatest empires is at stake