Stars John Franco, Rachel Weisz, Mila Kunis, Michelle Williams; directed by Sam Raimi; 130 minutes.

Two and a half stars

There's no place like home, Judy Garland learnt when she clicked the heels of her ruby slippers together and headed back to Kansas. But there's more than one story attached to the Land of Oz. L. Frank Baum wrote more than a dozen of them, and Gregory Maguire's novel, Wicked, was the basis for a hit Broadway musical of the same name that explored what happened before Dorothy set foot on the Yellow Brick Road.

Sami Raimi's Oz the Great and Powerful is an origins story that goes even further back - a tale of how the Wizard came to hold sway in the Emerald City. Part of this background is already explained in the 1939 movie, but it's filled out a little by screenwriters David Lindsay Abaire and Mitchell Kapner. James Franco plays Oscar Diggs, a shameless showman and travelling magician with an ingratiating smile, a trifler with the affections of various young women.

Fleeing an awkward situation, he is transported to Oz, hailed as a mighty wizard and long-awaited saviour, and expected to pit himself against powerful magic (embodied by witches Rachel Weisz and Mila Kunis).

There were legal constraints that didn't allow the filmmakers to reference the original too closely. But that's not really the problem.

What's disappointing about the movie is its failure to add anything significant to the Oz mythology - unlike Wicked, which developed relationships, themes and implications from the original, and created a strong story of its own. Oz the Great and Powerful really doesn't have much to say for itself. There are visual echoes of the original, particularly in the lush colour of the production design, but the movie soon runs out of ideas and emotional impact, and becomes a large-scale special effects scramble.