Gryllus the talking pig is back. Well, strictly speaking, he's a human in a pig's body . . . it's a long story. After saving the Cosmos once before, Gryllus is a bit tired of being a hero. He wants to return to human form and live a quiet life, preferably working as Chief Pie Taster to the Gods. The only person who can change him back is the demi-goddess Circe - but Circe, along with all the other Olympians, is nowhere to be found.
It looks like the Cosmos is in grave danger once again, and a mysterious prophecy seems to suggest that Gryllus might be the pig to sort things out. So, along with Sibyl the ex-priestess, the singing head of Orpheus, and an immortal grasshopper, Gryllus travels to the Underworld and back, and is surprised to discover just who is trying to destroy the Cosmos.