Fighting an implacable enemy in Germany, Marcus Aurelius trains his decadent son Commodus to succeed him, while rumor and intrigues brew back in Rome.

Commodus rises to power as Rome's new emperor, but not everyone supports his ascent. Among those conspiring against him: his older sister Lucilla.

Commodus defeats his sister's coup but withdraws from governing, allowing other to amass power while he engages in an affair and banishes his wife.

A disastrous grain shortage reaveals Cleander's treachery and leaves Commodus isolated, inspiring him to trains as a gladiator in a bid to unite Rome.

Lavish imperial games at the Colosseum are highlighted by the emperor's bloody victories, but his paranoid abuses of power lead to a final betrayal.