Caligula is summoned to Capri by Tiberius, his adopted grandfather. His escort is Macro, commander of the Praetorian Guard. Macro seeks to curry favor with Caligula, who will be the next Emperor, by tempting him with the promise of sleeping with Ennia, his wife. Frightened, but sycophantically eager to fall in with any mood of the mercurial Tiberius, Caligula has his first glimpse of absolute power as the aged Emperor leads him from his cavernous swimming pool through his grotto of pleasures. There, the two become voyeurs as youths and maidens act out Tiberius' fantasies.