Once Upon a Time season 5 episode 12
Emma with David and Snow White in Once Upon A Time season 5 episode 12 ABC

Emma Swan along with her Storybrooke heroes will go into the Underworld to bring back Hook to the land of the living in the upcoming chapter of Once Upon A Time season 5, which is also the show's 100th episode. Episode 12 is titled, Souls Of The Departed, which will air on 6 March at 8pm ET on ABC.

The official synopsis of the episode reads as follows:

Emma, Regina, Mary Margaret, David, Robin, Henry and Gold arrive in the Underworld, on a mission to rescue Hook, only to discover that their search will be more difficult than they had anticipated. The inhabitants of the Underworld - all souls with unfinished business and many with quite personal vendettas - hound our heroes at every turn. Meanwhile, in an Enchanted Forest flashback, a familiar face from the Evil Queen's past returns to present Regina with the perfect birthday gift, on the 100th episode of Once Upon a Time.

Click here to watch the episode via live stream on ABC, or click here to watch it online on ABC's official website in the US.

The episode will feature the return of many familiar faces like Regina's mother Cora, Peter Pan, and even Neal. Jennifer Morrison previewed Emma's journey to the Underworld in an interview with The Hollywood Reporter. Morrison said, "She is really leaning into the fact that she truly, deeply loves Hook and that she's going to risk everything to try and save him. We're going to this deep, dark place, and she's going there more full of love and hope and vulnerability than she's ever been before."

With Michael Raymond-James returning as Neal, there is a chance Emma will run into her former lover. Although Morrison did not reveal whom Emma will see in the Underworld, she hinted at "several fun surprises and unexpected encounters", as they try to find a happy ending for everyone.

Elsewhere a mother-daughter reunion between Cora and Regina will happen on the show's 100th episode. Lina Parilla who plays the Evil Queen said, "When she sees her mom for the first time, it's a happy reunion, but it's bittersweet. We start to learn why Cora's trapped down there, and we learn that Cora's there because Regina is part of her unfinished business."

#Oncers, we're not in Maine anymore. Travel to the Underworld with us when #OnceUponATime returns Sunday at 8|7c.

Posted by Once Upon a Time on Friday, 4 March 2016