In route to an Australian vacation via a steamboat, Dorothy is accidentally tossed overboard with Billina, a yellow hen that was also on the ship. They wash ashore in the Land of Ev, where Billina has gained the ability to talk. The two, along with Tik-Tok, a mechanical man who runs on clockwork motors, run into trouble and are imprisoned by Princess Langwidere.

Will Ozma and friends come to Dorothy's rescue in time? And how will they get to the Land of Ev from Oz? And just how will Dorothy get home this time?