Yellow Knight of Oz

In which Sir Hokus of Pokes sets off on a quest and discovers instead one of the greatest feats of enchantment in Oz history: two entire kingdoms transformed and hidden away for five hundred years by the evil Sultan of Samandra.
When a New York lad named Speedy rides a waywayd rocket ship to Oz, he arrives just in time to aid Sir Hokus and his noble steed the Comfortable Camel and to rescue Princess Marygolden from her enchanted life.