The gang was finally able to save Henry on the lastest "Once Upon a Time." But did they defeat Peter Pan for good?

In the episode, the heros try to resuscitate Henry (Jared Gilmore), while Pan looks on, gloating. Pan (Robbie Kay) says that he has Rumpelstiltskin (Robert Carlyle) trapped in a box.

Then in a flashback to Storybrooke, Regina (Lana Parrilla) adopts a baby. It's a closed adoption, so she will never be able to find out about the boy's genealogy or parents. She names the child Henry, after her father, who she had killed. 

Back in present day Neverland, Emma (Jennifer Morrison) tells the Lost Boys that she was a lost girl, but now has people who love and care for her. She tells them that Pan is not their family because he lies and is an evil person. One of the younger boys then cracks and tells them that Pan is at his Thinking Tree.

Emma, Snow (Ginnifer Morrison) and Regina are captured by vines once they get to the Tree. Pan says they are all bad mothers, and therefore cannot break free from the vines because they have regrets. However, Regina has no regrets because everything she has done, good or bad, has been for Henry, which allows her to break free.

She grabs Henry's stolen heart from Pan, as well as Pandora's Box. They go back to the Jolly Roger and put the heart back in Henry's chest. They anxiously hold their breath until Henry finally opens his eyes.

Regina then waves a hand over Henry, casting a spell that will make it impossible for anyone to take his heart again. Rumple, who is now out of the box, embraces Neal (Michael Raymond-James), and Emma also hugs her parents. But when they go to the downstairs of the ship, they see Pan trying to rip the heart away, once again, and steal his shadow. Rumple is then able to force Pan in Pandora's Box.

The group gets ready to leave Neverland, with Wendy and Tinkerbell on board as well. Everything seems wonderful until Henry opens his mouth. His voice is noticeably different as he tells one of the Lost Boys that "Pan never fails." Henry and Pan have switched bodies, meaning Henry's soul is trapped in the box and Henry has become the nefarious Pan.

On the next episode, "The New Neverland," the heroes return to Storybrooke, unaware that Pan has taken over Henry's body. However, Emma begins to sense that something is wrong. Hook and Neal will address their issues about their feelings for Emma, and Tinkerbell will try to find the Blue Fairy to try to regain her wings. Back in the Fairytale Land That Was, Snow and Charming (Josh Dallas) will search for a mythical creature that could stop Regina's evil ways for good.

Watch the promo for "The New Neverland," which airs Sunday, Dec. 8 at 8 p.m. EST on ABC.