When master builder Haterius constructs the Colosseum from the ashes of Nero's Golden House, his work is far from over. New Emperor Domitian tasks him with adding in a complex network of underground tunnels: the hypogeum. Haterius will have to balance satisfying the insatiable demands of the all-powerful Emperor, with the extreme pressures of creating an ancient architectural marvel in time for Domitian's games. Failure could cost his life.