A rainy day in Philadelphia means no baseball; Peter Brown,[2] the child protagonist introduced by Thompson in The Gnome King of Oz, mopes in his attic.

Toying with the coin and thinking of Oz, he wishes himself back in the magic land — and suddenly finds himself there, in the front yard of Jack Pumpkinhead.

By chance, Peter finds that his empty sack will fly from his hand and consume objects and creatures that are scooped into its open mouth, protecting him from danger.

Eventually Jack, with help from the Red Jinn (here introduced for the first time; his name, Jinnicky, is not revealed until later books), manages to save the day: using the Forbidden Flagon, he reduces Mogodore and his thousand warriors to little beings "no bigger than brownies."

The Pasadena Post referred to Jack's adventures as "strange and wonderful", and mentioned the Iffin as "one of the most curious and remarkable creatures ever discovered in Oz.