90 C.E. The Romans have conquered Britain but, while they occupy the barbarous province, are they really in control of the forces of nature...and unnature? The men of the Tenth cohort, manning a remote fort on the edge of the empire, think that military routine and tedium are the worst of their problems...But a new enemy is about to change all that. With a mad emperor, scheming senior officers, and comrades, slaves and lovers he cannot trust, Vallaunius the commander must learn, and learn fast. He must overcome his deadliest foe yet, and bring the five hundred barely-trained soldiers under his command through the ordeal. And alive. And if not alive, really, really dead!