"Oz the Great and Powerful" trailer debuts at Comic-Con

(CBS News) The first trailer for "Oz the Great and Powerful" is now online, after being screened Thursday during a panel on the film at Comic-Con.

The Walt Disney Pictures film, directed by Sam Raimi, is a prequel that stars James Franco as a circus magician with dubious ethics who gets swept away to the magical land, where he becomes the wonderful wizard of the title.

Pictures: Stars at Comic-Con 2012
"Oz the Great and Powerful": First official poster released

"Kansas is full of good men," he says in the trailer. "I don't want to be a good man. I want to be a great one."

In homage to the classic 1939 film, the trailer opens in black and white, and turns to color once Oz lands in Oz. There, he meets three witches - Glinda (Michelle Williams), Theodora (Mila Kunis) and Evanora (Rachel Weisz).

The trailer's final scene shows a green hand dragging its claws along a tabletop.

"Oz the Great and Powerful" opens in theaters on March 8, 2013.

Tell us: What do you think of the trailer?