When they accidentally uncover a plot against the British emperor Carausius, a young army surgeon and his soldier cousin are caught up in a maze of intrigue that leads them into an underground organization of secret agents in the service of Rome.

When they accidentally uncover a plot against the British emperor Carausius, a young army surgeon and his soldier cousin are caught up in a maze of intrigue that leads them into an underground organization of secret agents in the service of Rome.

Violence and unrest are sweeping through Roman Britain. Justin and Flavius find themselves caught up in the middle of it all when they discover a plot to overthrow the Emperor. In fear for their lives, they gather together a tattered band of men and lead them into the thick of battle, to defend the honor of Rome. But will they be in time to save the Emperor . . .