When Ares goes to Rome because he heard that his sister, Aphrodite, is in trouble, Xena finds him there when she goes up against the Roman Emperor Caligula who she'd heard is becoming a god. She and Ares find that Caligula is draining the immortality out of Aphrodite and Ares is determined to stop him before Caligula kills Ares' sister. Xena is able to stop Caligula but not before he becomes a full god and, as a result, Aphrodite becomes mortal.