As the film opens, Marcus Aurelius is the wise and revered emperor of the Roman Empire. When he decides that his heir apparent should be his adopted son Livius, his biological son Commodus and a conspirator poison him. Knowing that Livius is not nearly as politically ambitious as he is, Commodus convinces him to step aside. It is a move that Livius soon regrets: Commodus rules Rome with an iron hand, completely disregarding the well-being of the people and single-handedly reducing the grandeur of the Roman Empire. He sentences his own sister Lucilla to death and sets up a final confrontation with Livius that determines the fate of Rome.