401 BC e., Mesopotamia. Shahinshah Artaxerxes II, who had just ascended the throne of the largest state of the era, the Achaemenid power, conceived the murder of his main enemy - his brother Cyrus the Younger. Tom managed to escape, and he decided to overthrow the would-be fratricide with the help of Greek mercenaries led by the Spartan Clearchus, the former tyrant of Byzantium. In the battle on the banks of the Euphrates, the Hellenes showed themselves in all their glory, but the death of Cyrus made their further stay in the Persian possessions not only meaningless, but also mortally dangerous. Deprived of their livelihood, surrounded by enemies, they must make their way from the heart of the empire to their homeland...