A dark land filled with shadows and strange noises. A multiheaded beast standing guard. A new, sly ruler with a few tricks in store. A lack of Mutt Nuggets to fill Ares the pug's belly … The Olympians of Mount Olympus Pet Center have never faced a challenge quite like this.

With Zeus the Mighty trapped in his palace by an all-seeing guard dog named Cerberus, it's up to his gaggle of gods and goddesses to figure out how to rescue him. Once the Oracle speaks, the critters know they must venture deep into the belly of the vast Underworld to find the powerful relic that can free Zeus. But with so many new faces along the way, who can they trust? Will their quick thinking and teamwork be enough to save Zeus and themselves? After all, they found a way in, but can anyone really escape the Underworld?

Join Zeus the overconfident hamster, Athena the wise cat, Ares the treat-loving pug, Poseidon the proud pufferfish, Demeter the loyal grasshopper, and Hermes the daring chicken on another laugh-out-loud adventure through Greek mythology. And don't forget to check out the other books in the series : Zeus the Mighty: The Quest for the Golden Fleas (1) Zeus the Mighty: The Maze of the Menacing Minotaur (2) Zeus the Mighty: The Trials of Hairy-Clees (3)