Once Upon a Time, Ginnifer Goodwin and Josh Dallas

Though Once Upon a Time features such iconic fairy tale characters as Snow White, Prince Charming, Rumplestiltskin and the Evil Queen, the old adage that true love's kiss can break even the strongest curse has yet to be successful on the ABC series.

So what will break the curse that keeps hundreds of fairy tale characters trapped in the town of Storybrooke? The cast and creators of Once Upon a Time were on hand Sunday at a PaleyFest event, moderated by TVLine.com's Matt Mitovich, to answer that and other burning questions. Get the scoop:

Once Upon a Time bosses on breaking up Snow White, Prince Charming and more burning questions

1. The curse: Executive producers Adam Horowitz and Edward Kitsis clarified the rules of the curse, saying that only Henry (Jared Gilmore) is currently able to leave Storybrooke without consequence. We'll soon see more of how that rule affects those in the town. Since Mary (Ginnifer Goodwin) and David (Josh Dallas) have already locked lips on the show without breaking the curse, what's the secret? "They explained to us what breaks the curse — which I'm so not going to tell anybody — but once they told me, I kind of felt like a dumb-dumb because it makes perfect sense," Goodwin said. 

2. Emma's beliefs: Emma (Jennifer Morrison) is far from believing Henry's tales that everyone in Storybrooke is a fairy tale character, and that her parents are Snow White and Prince Charming. "There hasn't been anything that can really legitimately prove to Emma that this competently insane idea could ever be possible," Morrison said. "She's starting to realize there's something off and there's something wrong, but she's not sure what."

3. David and Mary's relationship: The producers have kept fans of the iconic couple frustrated watching them make up and break up over and over again. The latest roadblock: The mysterious disappearance of David's Storybrooke wife, Kathryn (Anastasia Griffith). "It certainly puts David in a place where he feels very guilty, very responsible for her disappearance, and it's an obstacle in the way of Mary and David," Dallas said. "Their love, and their unexplainable attraction is so strong, they'll always be drawn together."

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4. Archie's new patients: Archie (Raphael Sbarge) has been missing in action for a while, but he'll come back strong soon with two new patients: David and Mr. Gold (Robert Carlyle). "David's got problems," Dallas explains. "He's trying to figure out why he doesn't love [Kathryn] the way he used to or the way he's supposed to, and dealing with his feelings for Mary Margaret and why he has this pull and blinding love towards Mary Margaret that he doesn't have for Kathryn." For Mr. Gold, he enlists Archie's help because he essentially has no one else to talk to. Plus: We'll see Archie in Jiminy Cricket form again soon. 

5. The Stranger: Eion Bailey made a splash when his mysterious character, later revealed to be named August W. Booth, came to Storybrooke. He was last seen adding pages to Henry's fairy tale book with no mention of his true motives. "Before we get to the finale, we'll be pretty clear on who he is, what he's doing, why he wants to do it and how he's going to do it," Hororwitz said. One theory being thrown around is that the Stranger is actually a grown up Henry. Aside from pointing out that would mean adult Henry has an awkward attraction to his mother, the producers declined to comment on any of the theories.

6. Fairy tale world: The last we saw of Snow White, she desperately drank a potion that would make her forget Prince Charming because their love could never be. That will be explored in a coming episode. "As Rumplestiltskin has reminded us, all magic comes with a price," Kitsis pointed out. "So, to drink a potion and forget somebody you love has a price."

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7. New and returning characters: Following the Evil Queen's (Lana Parrilla) mention of The Little Mermaid in the Beauty and the Beast-themed episode, the producers say they're planning on featuring the Ariel story in Season 2, with plans for other princesses to come on as well. "Can I turn into Ursula at some point?" Parrilla joked to huge applause. As for fan-favorite character Sheriff Graham (Jamie Dornan), aka The Hunstman, who was killed in the midseason finale, Kitsis said, "[He] may have had his heart ripped out in Storybrooke, but he is still very much alive when we go back to fairytale land." Plus: True Blood star Kristin Bauer's Maleficent could pop up again, too.

Once Upon a Time airs Sundays at 8/7c on ABC.