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

The Germanic tribes strike as Marcus Aurelius succumbs to disease, leaving a skeptical Emperor Commodus to prosecute a war that doesn't interest him.

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 others to amass power while he engages in an affair and banishes his wife.

A disastrous grain shortage reveals Cleander's treachery and leaves Commodus isolated, inspiring him to train 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.