'Once Upon a Time' Season 3 Spoilers: Sunny Mabrey Cast as Glinda; Flashbacks to Reveal What Happened to Storybrooke Citizens

The Wicked Witch of the West will touch down in the world of "Once Upon a Time" when the series returns in March. Yet, viewers will see that the green-skinned sorceress has an unexpected softer side. 

When "Once Upon a Time" resumes, Rebecca Mader will assume the role of the Wicked Witch. Although the fall finale of the series saw Storybrooke vanishing into thin air, certain circumstances will restore Storybrooke and much of its population, which includes the Wicked Witch's "kindly" alter-ego. 

Ginnifer Goodwin, who plays Snow White on the series, told TVLine that the witch "is seemingly a kindred spirit to Snow White, which is part of what makes her so evil." 

"She seems so genuinely kind and has a way of becoming intimate with others and making them trust her.... Rebecca Mader called her 'Mary Poppins,' because she was just so damn likeable!" Goodwin said. 

Goodwin explains that Mader decided to tweak her character's Storybrooke persona to be especially scheming. 

"She wanted her to be manipulative and conniving, something of an investigator," Goodwin said. "But then she realized, 'No, what would actually be wicked would be to match Snow's sweetness and really seem like someone cut from the same cloth.'"

Jennifer Morrison hints that her character, Emma, could be the Dorothy in the Oz-themed scenario. 

"I'm not sure, but... a lot of this is about Emma accepting Storybrooke as her home, so I think that's where the Dorothy theme will come into it, that 'there's no place like home," Morrison said. 

And since there's a Wicked Witch, there will also be a good witch. 

TVLine reports that Sunny Mabrey has been cast as Glinda, the Good Witch of the South. 

Mabrey's Glinda has been described as elegant, warm and clever. While years of isolation have made her cautious, she is still optimistic. 

Mabrey has appeared in TNT's "Memphis Beat" and Lifetime's "The Client List."

Also, when the series resumes, viewers will see more of Christopher Gorham ("Covert Affairs"), and flashbacks will reveal how the citizens of Storybrooke landed back in the Enchanted Forest, where they run into familiar faces, who happen to harbor a huge secret. There will even be a shocking proposal that may not end happily. 

Captain Hook (Colin O'Donoghue) will also reappear in New York to enlist Emma's help, but first he has to help her remember her lost memories of Storybrooke and the Enchanted Forest. 

There will also be the return of "Once Upon a Time" iconography, as well as some scary flying monkeys. 

The spring premiere of "Once Upon a Time" airs Sunday, March 9 at 8 p.m. EST on ABC.