In spring AD 235, a surprise attack and the brutal murder of Emperor Alexander and his mother ends the Severan dynasty and shatters four decades of Roman certainty. Military hero Maximinus Thrax is the first Caesar risen from the barracks. A simple man of steel and violence, he will fight for Rome unconditionally. The Senators praise the new Emperor with elaborate oratory, but will any of them accept a Caesar who was once a shepherd boy? In the north, as the merciless war against the barbarians consumes men and treasure, rebellion and personal tragedy drive Maximinus to desperate extremes, bloody revenge, and the borders of sanity.