Talk about your wedding crasher.

This Sunday on ABC’s Once Upon a Time, bride-to-be Emma used the power of the song that had been inside her since before birth to thwart The Black Fairy’s first attempt at staging The Final Battle. Rumple’s mom, though, was down but far from out. 10 Shows on the Bubble

Instead, just as Emma and Hook exchanged vows (punctuated by a joyous duet-turned-group sing-along), The Black Fairy used the massive stash of fairy dust she had mined to unleash a new Dark Curse, one that snaked out of the clock tower and enveloped the wedding party and guests, as the episode came to a close.

“We’re well aware that we’ve done a curse ‘occasionally in the past,'” Once co-creator Eddy Kitsis notes with a wink, “but this time we’re trying to do a little twist on it.”

That’s because this particular dark curse was born out the need for a Final Battle that lives up to its name, between the savior, Emma, and Great Evil aka The Black Fairy. As co-creator Adam Horowitz explains, “It was less about thinking of it as a curse and thinking about it as, ‘What is the Final Battle?’ We had a concept for what this Final Battle would be and we kind of worked backwards from that. That led to this curse that you saw hinted at.”

Given the none-more-black nature of this curse, “The usual tricks don’t work anymore” to undo it, Kitsis warns. As Ginnifer Goodwin shared after a press screening of the musical episode, “The breaking of the curse involves something far more dramatic than anything that’s ever broken a curse before. If it were to break! We could all just be blown into oblivion, and that’s just it.”

Elaborating a bit on what it might take to vanquish this threat, Goodwin said, “What broke the very first season’s curse was a kiss — very pure, unromantic true love expressed between mother and son. The love that it takes in the finale… I feel is categorically bigger.”

Setting the stage as it does for their TV daughter’s Final Battle, Josh Dallas avowed, “It’s going to be a showdown of epic proportions,” while Goodwin said that although the face-off geographically goes down in Storybrooke, “Emotionally, they are all over the map.”

In addition to bringing to life the darkest of curses and accommodating The Final Battle, next Sunday’s two-hour finale also has the burden of giving closure to the characters and journeys that viewers have spent six seasons with, yet leave the door open juuuust enough to unfold a new tale — if the series gets renewed by Tuesday, May 16 (when ABC announces its schedule for the 2017-18 TV season), and knowing that a chunk of original cast won’t be returning in the fall.

“[The writers] found a magical way to make it go either way,” said Goodwin. “I mean, in classic Once Upon a Time style, there is a twist… and it serves all of the characters very well.”

Dallas realistically acknowledged, “You can’t please everybody. I think that some people will be happy and some people will be angry and upset.” But given that “each character gets something that the fans should be happy with, that each character deserves,” he added, “I think most people will be [happy].”

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