Though written in 1941, the book was not published until 1991. The first edition from Buckethead Enterprises of Oz featured a Foreword by the author's daughter Ozma Baum Mantele and illustrations by Gita Dorothy Morena, Kenneth Gage's granddaughter, plus an Afterword by Stephen J. Teller.
The Dinamonster is a giant robot, with cranes for arms and a three-story office building for its head. It was created by the Nome King as his vehicle for one more attempt at the conquest of Oz. The Dinamonster steals the Metachron — a clock powered by captured lightning — from atop the royal palace in the Emerald City. Since the Metachron governs time in Oz, Dorothy Gale, the Tin Woodman, and the Cowardly Lion set out to retrieve it.
When the Dinamonster steps on someone (as it often does), the victim is not squashed, but imprisoned within it. Dorothy and friends are captured in this way, and taken to the Nome Kingdom as captives. Glinda, the Scarecrow, and a boy named Tripp (who traveled to Oz by rocket plane) set off in pursuit. Tripp's cleverness and his flying skill are great advantages for the Ozzians, and in the end Ozma and Glinda are able to restore things to their proper order.