The winter finale of "Once Upon a Time" ended with a heartbreaking twist as Emma (Jennifer Morrison) was forced to kill the love of her life, Hook (Colin O' Donoghue) to save everyone in Storybrooke from going into the Underworld.

In the final minutes of episode 11, Hook was able to trap the Darkness in Excalibur, but knowing that it won't stay trapped forever, he begged Emma to kill him because he wanted to die a hero, and he wanted her to remember him as a good man. Emma tearfully told him that she didn't want to lose him, but after a while, she took the sword from Hook, kissed him goodbye, and stabbed him. Immediately, the Darkness left Emma and she was herself again.

But it looks like Emma will find a way to bring Hook back to life. After she found out that Rumple drew all of the Dark One's powers to himself, Emma asked him to take her to the Underworld to save Hook, and the final scene saw everyone, including Mary (Ginnifer Goodwin), David (Josh Dallas), Regina (Lana Parrilla), and Robin Hood (Sean Maguire), going on a boat as Emma vowed to find Hook.

Speaking with The Hollywood Reporter, co-creators Adam Horowitz and Eddy Kitsis talked about the second half of season 5, and they revealed some information about the Underworld and how the new setting will affect the characters.

"It's not hell. The underworld isn't hell—it is a place between," Horowitz explained. "It's a place for people with unfinished business, so it's not about good or evil."

Kitsis said that while the characters are looking for Hook, the second half of the season will be "a lot about them getting closure on their pasts and how the past comes to haunt you," so fans should expect more emotional moments when the show returns next year.

Season 5B will also feature new characters such as Hercules and Meg, and Kitsis revealed that their 100th episode will see a lot of people from the past who haven't been seen in a while.

"Once Upon a Time" returns Sunday, March 6 at 8 p.m. on ABC.