Hecate, demigoddess of magic and night, plots to take over the Underworld by planting a crystal on Hades' neck which slowly eats away his godly essence at the council of the gods, ousting Pain and Panic in the process. The two minions turn to Hercules for help, convincing him that "the devil you don't know is much worse than the devil you do know". Hercules is unconvinced that Hecate is worse than Hades, but he agrees to help restore him if they promise help in watching Amphitryon's sheep. Pain and Panic become attached to one who is about to give birth, while Hercules contends with Hecate for the throne, breaking the crystal. Hades, newly restored, blasts her out of the throne, and Amphitryon introduces Pain and Panic as the new sheep-sitters.
- This episode marks the first appearance of Hercules' adoptive father, Amphitryon, in the series. His second one is in "Hercules and the Parent's Weekend".
- Besides Cerberus and the Fates, the other Underworld residents summoned by Hecate are a Harpy and Memnon from "Hercules and the Living Legend".