Viewers will be taken on a trip down memory lane in the upcoming episode of "Once upon a Time" ("OUAT") season 6.

Titled "The Final Battle Begins," the next episode will feature the cast and executive producers as they look back on their favorite moments in the show's entire run. The one-hour special will also see the "OUAT" actors reminisce their characters' unique journeys over the past six seasons. Viewers will get a chance to see their favorite stars open up about what the series has meant to them and to the fans who have made "OUAT" a big hit on ABC. In addition, "Oncers" are given a special opportunity to ask cast members burning questions about the story.

Sunday's episode saw how music brought a lot of happiness and positivity to Storybrooke and the Enchanted Forest. However, the joyous dancing and singing during the celebration was cut short when the Black Fairy (Jaime Murray) unleashed her curse on the fairy-tale town. The credits rolled as the characters were surrounded by a cloud of dark smoke.

The curse will eventually send newlyweds Emma (Jennifer Morrison) and Hook (Colin O'Donoghue), alongside their loved ones, to a mysterious location where Emma will fight the Final Battle. Speaking with TV Guide, the show's creators shared some hints on what is ahead for the Storybrooke residents.

"I would say that the Final Battle and the curse are all tied in one, and the first act of the finale will make sense of what we're doing this time," co-creator Eddy Kitsis said.

Although this is not the first curse in the show's history, co-creator Adam Horowitz teased that they have prepared something special for fans. "There's a curse that's coming. We're well aware that we've done a curse occasionally in the past on the show, but this time we're trying to do a little twist on it," he added.

The sixth season of "Once upon a Time" airs every Sunday at 8 p.m. EDT on ABC.