Caligula ruled Rome for less than four years before he was stabbed to death in a corridor of his own palace at twenty-nine. The stories that survive him are lurid: he made his horse a consul, declared himself a living god, slept with his own sisters, and had senators' wives paraded for his amusement while purging the Roman elite on a whim. Historian Mary Beard sets out to test how much of that is fact and how much is hostile invention by later writers who never met him. She travels to the German frontier where he led a bizarre military campaign, to Capri where he built one of his pleasure villas, and through the excavated luxury of imperial Rome itself, reading the archaeology and the surviving texts against each other. Beard treats the sources as evidence to be interrogated rather than gossip to repeat, asking who wrote these accounts, when, and why they had reason to make Caligula look monstrous. The film ends without fully rehabilitating him, but with a clearer sense of where the myth was built.