In 1905, in Kansas, the small-time circus magician Oscar "Oz" Diggs is a weak, greedy, selfish and womanizer conman without character. He gives music boxes to the women that he seduces, and when a strong artist finds that his wife has a box in her belongings, he chases Oz through the circus. Oz flees in a balloon, but a tornado strikes his balloon and he lands on the Land of Oz. Oscar meets the gorgeous Theodora and she believes that he is the powerful magician from an ancient prophecy that will release her land from the Wicked Witch. Theodora tells that her sister and she are good witches, but the Wicked Witch had killed the king. Now the people are waiting for the magician to be their new king after defeating the witch. Theodora is seduced by Oz and brings him to the City of Emerald. When he sees the king's treasure, he decides to seek out the Wicked Witch and destroy her magic wand to get rid off her and become the king. Oz meets Glinda, who is supposed to be the Wicked witch, and soon he learns that Theodora's sister Evanora is the evil one indeed. Meanwhile Evanora lures he sister that is jealous and uses a spell to turn her into a wicked witch. Oscar learns that he is the only hope for the inhabitants of Oz that believe that he is a powerful magician and his only chance to defeat Evanora and Theodora is using illusion since he has no magic power.