It's a prequel.
Oz: The Great and Powerful is an upcoming 2013 fantasy film directed by Sam Raimi. The film, adapted from L. Frank Baum's 1900 novel The Wonderful Wizard of Oz, is intended as a prequel to the 1939 film The Wizard of Oz. The film stars James Franco as the protagonist. Mila Kunis, Michelle Williams, and Rachel Weisz star as the three witches.
Plot
The film's synopsis is:
Oz The Great and Powerful imagines the origins of L. Frank Baum's beloved character, the Wizard of Oz. When Oscar Diggs (James Franco), a small-time circus magician with dubious ethics, is hurled away from dusty Kansas to the vibrant Land of Oz, he thinks he's hit the jackpot with fame and fortune being his for the taking....that is until he meets three witches, Theodora (Mila Kunis), Evanora (Rachel Weisz), and Glinda (Michelle Williams), who are not convinced he is the great wizard everyone's been expecting. Reluctantly drawn into the epic problems facing the Land of Oz and its inhabitants, Oscar must find out who is good and who is evil before it is too late. Putting his magical arts to use through illusion, ingenuity, and even a bit of wizardry, Oscar transforms himself not only into the great and powerful Wizard of Oz but into a better man as well.
