The empire is on its knees, but a last hope lies beyond the eastern frontier . . . 377 AD: Emperor Valens has stripped the Persian frontier of its legions, sending every available man to Thracia in an effort to contain the rampaging Gothic hordes. Now, covetous eyes have fallen upon Rome's trade-rich but sparsely defended desert provinces. Shapur II, Shahanshah of the Sassanid Empire and his many client kings have long believed Rome's eastern holdings to be theirs by ancestral right, and those lands have never been more vulnerable. Thus, Valens must grasp at the slimmest of hopes that a Persian invasion can be staved off, not by the brute force of absent legions, but by the tenacity of a hardy few. For in the heart of enemy lands, something thought long lost might just offer salvation. When Optio Numerius Vitellius Pavo and a select group of the XI Claudia are summoned to the Persian front, they leave Thracia behind, knowing little of what awaits them. They know only that they are to march into a burning land of strange gods. They whisper tales of the mighty Persian Savaran cavalry and pray to Mithras they will see their homes and families again. All too soon it becomes clear to them that this is no ordinary mission - indeed, the very fate of the empire might rest upon their efforts. But for Pavo the burden is weightier still, for he knows that the east also holds something even more precious to him . . . the truth about his father.