In the far North of Gillikin Country lies the ancient kingdom of Pumperdink, a once-proud military stronghold that holds untold secrets of a long history against wicked witches and magical adversaries. But in the aftermath of a string of recent invasions that have occurred upon the soils of Oz, the walled nation has gone unnervingly silent, compelling a band of royal advisors from Princess Ozma's court to go and investigate.

While travelling the roads of the countryside, they encounter abandoned farmlands and decaying forests that paint an even grimmer portrait than they realized. And when they discover they are being stalked by a mindless crop of haunted animate pumpkins known as the Witherwalkers, they realize the beings are in search of something dark within the same walled kingdom they have their sights set on.

What evil lurks beyond the crumbling gates of Pumperdink? What sort of terrible reality has befallen its headstrong king and his loyal subjects? It is up to the Hungry Tiger, the Elegant Elephant and the Golden Gorilla to unravel the mystery, all while finding help from Princess Ozma, a race of underground fairies known as the Pearlfolk, and a long-lost soldier made of tin whose duty puts him on the same path as the weary travelers.