Late summer 116 AD. Across the deserts and ancient cities of Mesopotamia Trajan's grand war of conquest against Parthia rages on with no end in sight. Rome stands at the highwater mark of imperial expansion. Its borders stretching from the scorching heat of the Persian Gulf to the freezing forests and wastes of the Caledonian frontier.

Fergus is now second in command of the Fourth Legion. Assigned to garrison the great metropolis of Seleucia on the Tigris, he and his small command are soon caught up in the thick of a major uprising against Roman rule. A rebellion that will stretch Roman resources and determination to breaking point and determine the limits of empire.

Meanwhile back on the island of Vectis off the southern coast of Britannia, Marcus, Fergus's father, has become a fugitive. Run out of Rome and stripped of his position by powerful senatorial enemies who want his head, Marcus returns home, knowing that he and his family stand on the brink of complete disaster. Stubbornly refusing to abandon his farm, Marcus resolves to find a way in which to stave off his powerful enemies and ensure his family's survival. But the odds are heavily stacked against him.