The Moors have invaded the Iberian peninsula, raiding and pillaging Roman towns, but the people of Tarcisis turn a blind eye to the danger. Made complacent by the prosperity of the Pax Romana, they focus instead on the sadistic Games and on the persecution of members of a new religious sect living within the city walls - the Christians.

Striving always to adhere to the principles of his hero Marcus Aurelius, Lucius musters all of his moral courage and sheer strength of will to protect the city. His devotion to civic duty undergoes a crucial test, however, when the charismatic and beautiful leader of the new sect, Iunia Cantaber, is brought before his court. Mario de Carvalho depicts the timeless story of a good man struggling to maintain sense and order in his public and private lives and to uphold justice as he understands it.