Sixteen years after Marcus Aurelius’s death,[a] Rome is ruled by the corrupt twin emperors Geta and Caracalla. In the North African kingdom of Numidia, Hanno lives with his wife, Arishat. The Roman army led by General Justus Acacius invades and conquers the kingdom, killing Arishat and enslaving Hanno and the other survivors. The enslaved people are taken to Ostia, where the Romans pit them against baboons to advertise them as potential gladiators. Hanno savagely kills a baboon, impressing the stable master Macrinus, who promises Hanno an opportunity to kill Acacius if he wins enough fights in Rome.
Acacius returns to Rome as a war hero. Geta and Caracalla prepare gladiatorial games in the Colosseum to celebrate. Acacius asks for a break from war with his wife Lucilla, Aurelius’ daughter, but the emperors refuse and plot to conquer Persia and India. Senator Thraex hosts a party for the emperors, featuring a gladiatorial duel. After Hanno wins, he recites a verse from Virgil’s Aeneid, revealing his Roman education and raising Macrinus’ suspicion. Acacius and Lucilla conspire with Thraex and Senator Gracchus to overthrow the emperors and restore the Republic.
Hanno emulates the late legendary gladiator Maximus in the Colosseum to win fights. Lucilla realizes that Hanno is her son, Lucius Verus, whom she sent away as a child to protect him from rivals for the throne. Lucilla visits Lucius and tries reconnecting with him, but he angrily rebuffs her, believing she had abandoned him. Lucilla reveals to Lucius that he is Maximus’ son and tells him to use his father’s strength to survive. During a naumachia in the Colosseum, Lucius leads the gladiators to victory and fires a crossbow at the spectating Acacius but fails to kill him.