A.D. 255: The Roman Imperium is stretched to the breaking point, its authority and might challenged throughout the territories and along every border. One man is sent to marshal the defenses of a lonely city and to shore up the crumbling walls of a once indomitable symbol of Roman power, a man whose very name means war, a man called Ballista. So unfolds an epic drama-a story of empire, heroes, treachery, courage, and most of all, of brutal, bloody warfare.