The death of Tiberius vaults Caligula to power as Rome's new emperor, a role at which he initially excels -- until an illness unhinges his mind.

Vulnerable without an heir, Caligula decides to secure the throne with a child of royal blood by embroiling himself in affairs with his three sisters.

Caligula's increasing paranoia and debauchery lead to ruinous bloodshed and spending as Rome, the Senate and even former allies turn against him.