Credit: ABC

Warning: This story contains major spoilers from Sunday’s episode of Once Upon a Time. Read at your own risk.

Snow White and Prince Charming aren’t the heroes that Once Upon a Time fans thought they were.

During Sunday’s episode, Snow (Ginnifer Goodwin) and Charming (Josh Dallas) did everything in their power to keep Ursula (Merrin Dungey) and Cruella de Vil (Victoria Smurfit) from resurrecting Maleficent (Kristen Bauer van Straten), who was harboring a dangerous secret about the Charming family.

While it initially appeared that Snow and Charming were desperate to prevent the Queens of Darkness from revealing that Emma (Jennifer Morrison) has the potential to turn evil, the secret was even more dangerous than that: In the past, the heroes not only risked the safety of their kingdom to make sure Emma didn’t turn evil, they also ultimately caused Maleficent to lose her own child.

“That’s the tip of the iceberg of the secret that you saw in the second episode,” executive producer Adam Horowitz reveals. “Our hope is that by the time everything is revealed, you’ll see it really informs who they were in season 1 when you met them for the first time.”

In the past, Snow and Charming briefly aligned with the Queens of Darkness to find the Tree of Wisdom in a bid to prevent the Evil Queen (Lana Parrilla) from releasing the Dark Curse. But the tree rejected the heroes because Snow was already pregnant with Emma, who had the potential to become evil. Mal then personally visited Snow in the night, pleading to align so she could protect her own child, but Snow White knew in doing so would cause Emma to eventually become evil and rejected her.

“We hope that in seeing the second half of the season that you will go back and look at the series in a different way,” executive producer Edward Kitsis says. “Just like at the end of the second episode you realize Maleficent isn’t just a villain, she was a mother trying to protect her kid. If you rewatch [episode] 13 and you rewatch everything she’s doing, it hopefully gives more depth to it.”

Now in the present, Mal plans to make Snow White pay for her past mistakes. “We find out so much more about that storyline as we go forward and what’s fueling her,” Bauer says. “She is half-reptile and even in human form, humans are incredibly protective of their young, but I’d like to think of her as animalistic in what lengths she would go to. She could be fairly cold-blooded, no pun intended, but literally.”

Mal’s path to getting vengeance will be slow going—but for good reason. “As a villain, the first step is just patience,” Bauer says. “They watch and they wait and they have time on their side. They’re not going to ever allow or settle for a quick death. They will wait for their opportunity to exact the longest and most amount of pain possible, that’s her goal.”

It sounds like getting justice for the loss of her child will include corrupting Snow’s, though Bauer notes that there’s a fine line between what the villains are trying to make happen with Emma and what fate has in store for the Savior. “Are villains made or are villains born that way?” Bauer says. “How much can you change your spots?”

In turn, Snow White has already enlisted the help of Regina to infiltrate the Queens of Darkness in hopes of protecting her family. But will Regina be able to handle walking on the dark side again without turning evil? “There’s always an element with Regina of coming to terms with what she was and what she wants to be,” Horowitz says. “Regina can walk in that world with a little more confidence and a little bit more safety.” But, Kitsis adds, “Regina is going to have a huge curveball thrown her way in the second half.”

The first step for Regina, however, is proving to Mal that she isn’t a good guy. “Regina has become a good girl and to Maleficent, that is pathetic,” Bauer says. “She’s going to have to convince Maleficent that she’s more Evil Queen than good, that she’s still the friend that she knows. These women have a love and affection and respect. Maleficent is ultimately half-reptile, so there’s nobody she won’t destroy, step on, kill, cause pain for who gets in the way for what she needs and wants.”

As Regina is tempted by the dark side, will she accidentally reveal Emma’s big secret? “Snow was asked to keep a secret and couldn’t keep her mouth shut,” Horowitz says. “Can Regina keep her mouth shut? Regina is probably a stronger and better secret keeper than Snow White, but it does create a bond between the two of them. She was her step-mother.”

As for whether we’ll find out who Maleficent’s baby daddy is, Kitsis replies, “If there is one.” Does that suggest Mal could be lying? “I’m suggesting this is a show where Dwarves are hatched from an egg,” Kitsis adds.

Once Upon a Time airs Sundays at 8 p.m. ET on ABC.