During the emotional winter finale of "Once Upon A Time," Killian/Hook finally overcame the darkness within him and sacrificed his life for the well being of his loved ones. Heartbroken, Emma is on a mission to bring him back. In order to do so, Emma and the rest of the Storybrooke characters will have to go to the Underworld to find him.

Season 5 of "Once Upon A Time" is currently on hiatus and isn't expected to return until March 2016. Thankfully, executive producers Adam Horowitz and Edward Kitsis spoke to Entertainment Weekly to reveal a few tidbits about the second half of season 5.

According to the producers, the characters will travel to the Underworld but will not spend the rest of the season there. Viewers can also expect to see different characters in the Underworld as the producers have revealed that it is not full of villains only.

While villainous characters like Cora, Peter Pan, Cruella de Vil are set to return, viewers will also be introduced to new characters including Hercules and Megara. Hades has been revealed to be the new villain of the season.

In the Underworld, characters will still be able to kill and die but will be subjected to a new set of rules and consequences. "There are things that apparently worse than death," Kitsis revealed. Characters who have already died can be defeated but not using conventional weapons. This tidbit will be important for Regina as she will come face to face with many of her victims.

Regina and Emma will both be using magic in the Underworld and will find themselves working together again. Emma will try to split her heart to share it with Hook, but the tasks will definitely not be easy.

Unfortunately, Horowtiz and Kitsis have not revealed whether Hook can be brought back to life. "He may die there. To be honest, he's already dead," said Kitsis.

Hopefully, Emma will find a way to save Hook. It has already been heavily hinted in the past few seasons that Emma and Hook may be each other's happy endings.

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