Sian Phillips narrates a look at how Tiberius and his notorious successor Caligula dragged the Roman empire into an age of tyranny, incest, and shocking depravity. Tiberius became Rome's second emperor with understandable paranoia and trashed what was left of democracy by making it punishable by death to speak out against him. With no son to name as heir, Tiberius invited his teenage nephew Caligula to join his court, but when the emperor fell ill, Caligula seized his chance to gain power and had him smothered on his sickbed