‘Once Upon a Time’ (OUAT) Season 5 episode 12 spoilers,

‘Once Upon a Time’ (OUAT) Season 6 episode 1 spoilers, airdate: When will the show premiere? What’s next for Emma, Hook, Regina and other heroes? (Photo : Facebook/ Once Upon a Time/ ABC)

"Once Upon a Time" (OUAT) Season 5 returns with its highly-anticipated episode 12 on March 6, Sunday. It is a landmark segment titled "Souls of the Departed" and it marks the 100^th episode of the fairytale drama series. Emma and the other heroes will be visiting the Underworld in search of Hook. Here are spoilers and promo for the midseason premiere. Read on to find out what happens next. Also, find out where to watch online via live stream.

Like Us on Facebook

[Spoiler alert! This article contains spoilers for "Once Upon a Time" (OUAT) Season 5 episode 12 "Souls of the Departed." Do not read further if you don't want to know more about it.]

During the events of the midseason finale, Hook made the great sacrifice as he took the darkness onto himself and saved Emma. As "Once Upon a Time" Season 5 resumes its run, episode 12 picks up from where the show left off in episode 11.

According to the synopsis for the 100^th episode on ABC's official website, the Storybrooke heroes won't give up on Hook. The plot details for forthcoming segment brings back some new and familiar faces, including Greg Garmann as Hades, Robbie Kay as Peter Pan, Barbara Hershey as Cora, Tony Perez as Valet, and Giancarlo Esposito as Sidney Glass.

Emma, Regina and others go after Hook to the Underworld. Upon arrival, they realise that their mission has several obstructions and it is going to be a tough journey. The Underworld seems to be a lot different than they had anticipated. Emma, Mary Margaret, David, Robin and all the others on the mission must deal with the departed souls with "unfinished business and quite personal vendettas" in the Underworld.

A flashback of an event that took place in the Enchanted Forest, features Regina's encounter with someone from her past. This person brings a "perfect birthday gift" for the Evil Queen. A recently released promo video for "Once Upon a Time" (OUAT) Season 5 teases Regina's interaction with Mary Margaret in the forest. Scroll down to watch the video.

Second trailer for the midseason premiere sees Snow White's encounter with David's twin brother James in the Granny's Diner. James enters the diner and kisses Snow White without introducing himself to her. This leaves her unsettled and agitated. She is soon joined by David, Emma and Gold. Find the promo video below.

According to The Hollywood Reporter, the surprise encounters leads to an "emotional journey" for everyone, who is a part of this mission. However, the "Once Upon a Time" actress Jennifer Morrison, who plays the role of Emma Swan, revealed that her character will be affected the most.

"Emma 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." Morrison said. "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. ... I think her having gone through the "Dark Swan" phase has given her the opportunity to be that open and vulnerable, and it's almost like looking at her own inner demons in a certain way in order to get to a more open, free place and the other side of it," she explained.

"Once Upon a Time" (OUAT) Season 5 episode 12 "Souls of the Departed" airs March 6 at 8:00 pm on ABC. Fans can watch the 100^th episode online through live stream on abc.go.com. Meanwhile, stay tuned for more spoilers and update.