Over two decades after the events of Gladiator (), Lucius—the grandson of Rome's former emperor Marcus Aurelius and son of Lucilla—lives with his wife and child in Numidia. Roman soldiers led by general Marcus Acacius invade, forcing Lucius into slavery. Inspired by the story of Maximus, as depicted in the original film, Lucius resolves to fight as a gladiator while opposing the rule of the young emperors Caracalla and Geta.