The triumphant heroes returned from Neverland on "Once Upon a Time," but little did they know that evil was lurking right under their noses.

As the ship drops back in to Storybrooke from Neverland, there are congratulations all around. Then the happiness fades as Peter Pan, who is trapped inside Henry, imprisons his servant Felix, then watches as Rumpelstiltskin (Robert Carlyle) seals Pandora's box, with Henry (inside Peter Pan) locked inside.

It then goes back in time to the Fairytale Land That Was. Evil Queen Regina (Lana Parrilla) is crashing the wedding of Snow White (Ginnifer Goodwin) and Prince Charming (Josh Dallas). Snow thinks up a plot to get back at the Evil Queen during their honeymoon. She wants to use Medusa to turn Regina into stone and then behead Medusa. However, it fails when their sword breaks against Medusa's neck. Charming tries to distract Medusa while they run, but it doesn't work, and Medusa turns Charming into stone. But Snow is able to let Medusa's own reflection turn her into stone, thereby freeing Charming.

In Storybrooke, Emma (Jennifer Morrison) sees that something is odd about Henry. Regina also takes Tinkerbell (Rose McIver) to the Blue Fairy to get her wings back, but it is to no avail. Meanwhile, Neal (Michael Raymond-James) wants to repair his relationship with Emma.

Pan-as-Henry then thinks up a plan to take out the Blue Fairy, which would allow him to gain her magical powers. He lets Regina believe that he is in need of protection, so she decides to take him to the Blue Fairy's crypt to keep him safe, which is where all of her magic is held.

Once the rest of the gang finds out that Pan is after Henry, they release Henry-as-Pan from Pandora's Box. Pan tries to convince Emma that he is really Henry trapped in Pan's body, saying that she gave him up for adoption to give him a better life.

Although Emma and the rest know the truth, Regina is still in the dark. In the safehouse/crypt, Pan-as-Henry knocks out Regina with a smoky potion.

Pan-as-Henry is trying to rekindle the broken curse, in which everyone would lose their memory again and be stopped in time.

On the upcoming midseason finale of the series, "Going Home," Pan will try to reactivate the curse to become the evil leader of the "new Neverland."

Series co-creator Adam Horowitz told TVLine that "Pan has regrouped and come up with a Plan B that is probably even more devastating and intense.

"The midseason finale is meant to tie up all of the arcs and loose ends from the first half of this season, while also endeavoring to carry over the story into what we are hoping is a compelling new mode of storytelling in the second half," Horowitz continued.

Co-creator Edward Kitsis added, "By the end of Episode 11, most of the loose ends are tied up. Like, 'Does Tink get her wings back?' - all these questions will be answered. It will feel very much like a season finale, and we are very much setting up what will be a season premiere in March."

When the series returns on March 9, the new narrative will be focused on Storybrooke and The Enchanted Forest.

Viewers will also see a new, yet "familiar" evil, played by "Lost's" Rebecca Mader. Rapunzel will also be introduced, who will be portrayed by Alexandra Metz ("Originals"). Metz will make her debut in the 14th episode of season three.

"We have some intriguing surprises in the season finale," Horowitz said. "We've obviously been building to this all season, with the mindset of using it as a launching pad for the second half of the season. We hope the audience digs in and sticks with us!"

Watch the promo for "Going Home" below, which airs Sunday at 8 p.m. EST on ABC.