Regina (Lana Parrilla) will attempt to pull off a big scheme in the next episode of ABC's Once Upon a Time in order to save herself and her fellow heroes.

With Hades (Greg Germann) and Zelena (Rebecca Mader) together again in the Underworld, the villains are hoping to trap the heroes there forever. ABC has released a plot synopsis for the episode that details what's ahead for them and how Regina is hoping to stop them.

"Now that Hades and Zelena are reunited, Hades tells Zelena that he wants a future with her outside of the Underworld. All she needs to do is heal his heart with True Love's Kiss so they can leave the Underworld and trap the heroes there for eternity," the synopsis reads. "When Regina overhears of this plan, she enlists Cora's [Barbara Hershey] help to find a way to separate Zelena from Hades. However, Cora reveals a family secret that could change Regina and Zelena's lives forever. Meanwhile, David [Josh Dallas] finally meets James, only to realize that his twin is determined to seek revenge on him for stealing the life he could have had."

Guest stars for this episode include Hershey as Cora, Robbie Kay as Peter Pan, Victoria Smufit as Cruella De Vil, Tony Perez as Valet, Adrian Hough as Woodcutter, Ava Acres as Young Regina, Isabella Blake-Thomas as Young Zelena, Romuald Hivert as Guard and Germann as Hades.

The promo for the episode (titled "Sisters") focuses on both storylines discussed in the synopsis. Regina vehemently tells Zelena that Hades is "a villain" while Zelena responds, "Stop pretending you care about me." Meanwhile, Cora tells Regina that Zelena is in "more danger than you realize."

The other part of the promo features David and James facing off, with the voiceover stating that this could turn into a "war" between the brothers.

This episode is slated air Sunday in the regular OUAT timeslot.

Once Upon a Time airs Sundays at 8 p.m. ET/PT on ABC.

Watch the promo for the next episode of Once Upon a Time here:

Tags
Once Upon A Time, Television, ABC