Dorothy and Uncle Henry are sailing to Australia. Waking up, Dorothy cannot find Uncle Henry in the cabin and decides that he went on deck. In fact, Uncle Henry was sleeping, covering himself with his head, but Dorothy did not notice him. Once on the deck, the girl grabs the bars of a large chicken coop so as not to fall overboard, but another gust of wind flies up, and the chicken coop is in the water with Dorothy. The lid of the chicken coop flies off, the hens and roosters are drowning, but Dorothy, holding on to the rods tightly, is floating on the chicken coop raft wherever it is. The storm abates, and Dorothy, settling in a corner, falls asleep.

Having woken up in the morning, the girl realizes that she is not alone on the raft. Nearby, a yellow chicken who has just laid an egg clumsily merrily. She knows how to speak and informs Dorothy that her name is Bill, but the girl renames her Billina, believing that such a name befits a chicken more.

Soon the raft beached, Dorothy and Billina landed. They find the cave, and in it the mechanical person Tik-Tok, who starts up with a key and knows how to move and talk. Tick-Tok informs Dorothy and Billina that they arrived in the country of Ev. King Ewoldo, who ruled here, once in a fit of anger once sold his wife and ten children to the King of the Dwarves, who with the help of witching charms turned them into trinkets for his underground palace. Then, repenting of his deed, Ewoldo began to beg the Dwarf King to return his family to him, but he became stubborn, and then the unfortunate Ewoldo threw himself from a cliff into the sea and drowned.

Now, in the royal palace, the niece of the king, Princess Langwider, lives. State affairs do not interest her. Day-to-day she turns in front of a mirror and tries on one or the other head, of which she has thirty-two pieces. When Dorothy arrives at the palace, the princess demands that the girl give her head to her in exchange for head number twenty-six. Dorothy refuses, and the angry princess imprisons her.

But Dorothy did not languish there long. Just at that time, Princess Ozma, the young ruler of Oz, decided to rescue the royal Eva family from the underworld. Ozma is accompanied by the Scarecrow, Ironman, Cowardly Lion, The Hungry Tiger, as well as an army of twenty-six officers and one soldier. They free Dorothy and continue the campaign together.

They manage to find their way into the underworld, but the Dwarf King refuses to free the captives. He is not afraid of the power of Ozma, for he himself is very good at conjuring, and his army is numerous and excellently armed. However, the underground monarch invites them to play a game. Each of the members of the expedition receives the right to try to guess what exactly the queen of the country Ev and her children turned into. One who does not guess even once turns himself into a decoration in the palace, and the next one gets one more attempt. Gradually, all members of the expedition become trinkets, replenishing the collection of the King of the Dwarves. Only Dorothy accidentally succeeds in guessing once, having resurrected the little prince. This saves her from becoming a decoration, but does not save the rest. But then Billin gets down to business. Hiding under the throne, she overhears the King’s conversation with the Dwarf Administrator and finds out what the monarch turned his uninvited guests into. She demands that she be allowed to try her luck in a "guessing game", and the King does not want to hear, but it turns out that he has a weak spot. He is terribly afraid of eggs, and Billina just demolished one such thing under the throne. Only when he gives permission to Chicken to guess, the Scarecrow removes the egg, hiding in the pocket of his coat, where he already has one that was laid down by Billina on the way. Of course, the Yellow Chicken brings everyone back to life, with the exception of the Lumberjack.

The Dwarf King, however, does not intend to give in so easily. He threatens Ozma and her friends with terrible punishments, but here the Scarecrow launches Billina's eggs in him. Taking advantage of the panic, friends take off his Magic Belt from the King, depriving him of his main strength. But even under the threat of turning into an egg, the King is unable to track down the Lumberjack, and judging by it, he does not lie.

With a mixture of joy and sadness, Ozma and her companions begin their journey back. The king desperately sends them an army of his fellows in pursuit, but the Magic Belt turns the front lines into eggs, and the army flees in horror.

On the way back, the insightful Billina notices that the little prince, freed by Dorothy, took out a small iron whistle from somewhere. It turns out that he slowly borrowed it in the underground palace, and this whistle is nothing more than an enchanted Iron Lumberjack. The Magic Belt returns to its former appearance, and now nothing is overshadowing universal glee.

The country of Ev has a new king - the elder prince Evardo. Then Ozma and his friends return to the Emerald City. Dorothy is happy to visit the palace of her new friend Ozma, but one day she notices a magic picture in one of the rooms of the young princess, which shows everything that is happening in the world. Dorothy asks Uncle Henry to show her in Australia and, seeing his exhausted, worried face, asks Ozma to quickly transfer her to him. The Magic Belt here comes in handy. Uncle Henry is happy to see Dorothy alive and well. However, before parting, Ozma and Dorothy agreed that on Saturdays the young princess would call up the image of Dorothy in the picture, and if she gave a conditional sign, she would immediately find herself in Oz.