Once Upon a Time season 5
Emma and Hook in Once Upon A Time season 5 winter finale ABC

Once Upon A Time season 5 will return from its mid-season break on 6 March, at 8pm EST. ABC has released the synopsis for its 100th episode titled, Souls Of The Departed, which teases a lot of underworld adventures ahead.

Here is the synopsis for episode 12:

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.

According to executive producer Edward Kitsis, the mission to save Hook from the Underworld will quickly be expanded once Emma and the gang reunite with old friends and foes. Kitsis told Entertainment Weekly, "The second half is going to be very similar to the first season in that we're going to see Storybrooke as a place of people with unfinished business. We have to wonder if we can't help them find their happy endings even in the afterlife."

The season 5's second half will bring back saviour Emma. Executive producer Adam Horowitz told EW. "Emma is absolutely bada**. She is a tough women."

Kitsis added, "I've got to be honest. I feel like Emma's been pretty much bada** for five seasons. I don't know what season she wasn't bada**. She killed Cruella [Victoria Smurfit]!"

In the winter finale, Hook sacrificed himself to take down all the Dark Ones including Emma. By the end of the episode, Emma swore to bring the love of his life back from Underworld and left on a journey to rescue him from eternal damnation.

Actress Barbara Hershey will return as Regina's mother Cora, Giancarlo Esposito will return as Sidney Glass/Magic Mirror, Robbie Kay's Peter Pan will also make an appearance.

Michael Raymond-James will return as fan-favourite character Neal Cassidy aka Baelfire for the show's 100th episode. Previously, Kitsis teased if Neal's name would come up as Emma, Rumple and others travel to Underworld. The producer said, "I think that it would be very disappointing for her to go down there and not have somebody talk about Neal."