Music brought a lot of happiness to the Enchanted Forest and Storybrooke on Once Upon a Time Sunday night, but only for a brief while.

When the singing quieted down and the dancing stopped, the Black Fairy (Jaime Murray) unleashed her curse on the fairy tale town and descended all of its inhabitants into a cloud of dark smoke as the credits rolled. The curse will send newlyweds Emma (Jennifer Morrison) and Hook (Colin O'Donoghue), along with everyone they love, to a mystery location so Emma can fight the Final Battle.

The ominous ending is setting up quite an adventure for the two-hour season finale which airs Sunday, March 14., along with a small group of reporters, was able to talk to Once creators Adam Horowitz and Eddy Kitsis about the cliffhanger ending what everyone can expect from the final two hours — especially if they are the series' final hours and not just the season's.

Jennifer Morrison and Colin O'Donoghue, <em>Once Upon a Time</em>Jennifer Morrison and Colin O'Donoghue, Once Upon a Time

The episode ends with the curse hitting. What can you tease of what has transpired going into the finale?

Adam Horowitz: 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.

Eddy Kitsis: 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.

Is there a geographic move, because they're talking about how everyone is going to be split up?

Kitsis: For some people, there may be a geographic move.

Horowitz: It's a combo platter kind of curse. There's a bunch of different things that happen.

Kitsis: The Black Fairy is not to be messed with. She's got some airtight [plans].

When you approach a curse, what's the thought process behind it? Any set rules?

Horowitz: In this case, 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 and that led to this curse that you saw hinted at in the musical episode that then starts to play out in the two-hour season finale.

Will everyone make it out alive?

Kitsis: Can't promise you that.

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Can you talk about the process of breaking the curse?

Kitsis: I would say that how they're going to break the curse is kind of the conundrum of the episode because the usual tricks don't work anymore.

So if this ends up being the series finale instead of the season finale, how do you think fans are going to react to it? Is it going to be a Lost type of thing where people are going to be up in arms?

Kitsis: I would say that if this was the series finale then you would have the usual opinions on a series finale, ranging from the best ever to the worst ever because that's the Internet. What I would say for fans is that it will be complete, so they will not have any dangling threads where they're like, "I can't believe they..!" We're not going for a crazy ending that everyone goes, "Well, what does that mean?" And "I feel unsatisfied" or "I'm not feeling like you came for the characters" or whatever. We understand that this could be the last year so we aren't — trying to hope for the best. We feel like we've completed this story and the next chapter of Once Upon a Time will be completely different.

On the flip side, you are having the final battle in the finale. If this is a season finale and not a series finale, can you talk a little about how you move past the final battle, what is that show?

Horowitz: I think the way we sort of look at it is these are stories for these characters and there are set end points to different stories but that doesn't mean that there aren't new stories for different characters. So I think that by the end of the season finale, a lot of what we've been doing for the last six years is wrapped up in a very satisfying way and then we move forward in a way that at the end of it, hopefully you'll see what we're hoping to do in Season 7.

Kitsis: Yeah I think if there's one thing this show has done, it's reinvented itself every year and so this show has the ability to be many different shows so we feel like creatively it's time to end a few stories but the new show, we feel like this is the kind of show that regenerates. And I think when you see the ending you'll go, "Oh yeah!"

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What can you say about Rumple's part in the finale?

Kitsis: I will say the final battle will be thematic for everybody and that Rumple, as a man who is a difficult man to love, I think he will have a very difficult choice to make again.

What is the thematic through line?

Kitsis: I would say the theme of the final two hours is belief.

You talked about the finale being the end of certain characters' stories. Assuming there is a Season 7, will the door still be open for people to return?

Kitsis: Yes.

Horowitz: ...We're not designing this in a way that we're going to say goodbye to everyone and never see them again. As I said, it's like we've been telling a story for six years now, for these characters, and now we're trying to complete that story, but that doesn't mean they don't have other stories.

If you were to continue the story, and some characters took a step back from the storyline, could you make a minor character be more of the center of focus, or introduce someone new?

Katsis: I would say we would introduce someone new, if other characters were taking a back seat...I would say that probably if you think the reboot is going to be, "Oh my God, it's Bashful and Sneezy on a road trip," the network did not go for that.

But [we were] thinking, would it be like Cinderella or Ruby, people we haven't seen in a while?

Horowitz: I would say this, in all seriousness. It's a combination of things that we're planning to do. So it's like, while we don't want to say literally what we're hoping to do, but it's not — it would involve our characters, some of our characters, and it would involve some new people as well. It's a mixture of things.

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Speaking vaguely about the finale, what are some of the characters that you're most happy with their journey and arc from the beginning of Season 1 to the end of Season 6 once we get to the end of the finale?

Kitsis: Absolutely Emma.

What do you think she learned the most?

Kitsis: I think she learned to trust other people, and I think that's the hardest thing to do, is when you are used to being on your own, it's very hard to let someone in and have it be real. It's very easy to be surfacey and "like" their stuff on Facebook; it's hard to actually be the person they call, and I think that Emma has gone from somebody that slept in her car and denied she had a kid to someone who actually has found a real life, and to me, that's kind of like — that says the show, right there.

Horowitz: I agree, and I would say adding to that also Regina, who has gone through so much from where she started in the pilot to where she is now. I'd say in the season finale, there are real echoes to the pilot and where she began and where her and Emma began and where they are now. It's been a tumultuous journey for both of them as they've grown and changed over the years. For us — and hopefully you and the fans will agree — we think it's a satisfying place they find themselves.

Can you talk about Emma and Killian's vows? Were there many iterations? What did you want them to convey?

Kitsis: You know, yes. We knew that the wedding would be a big deal, but we knew that the vows would be a big deal, and we didn't want them sung. We felt like, in that moment, the audience who was a fan of those two as a couple has waited since Season 2 to say that; they don't want it in a song with a hundred people. We wanted to really just slow the moment down and let it be between the two of them, and then have everyone come into it. It probably went through a lot of different iterations.

Horowitz: Like any script, there's lots of drafts and you kind of work it and fine tune it. It's certainly something we've been thinking about for a long time.

Kitsis: And they're registered at Pottery Barn, if that's what everyone's asking. They need towels.

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Is Belle in the finale, and what is her piece in that?

Kitsis: Yes. Basically, we kept Belle out because of all the [hijinks] from the last episode. They were playing coy what they were doing. She will very much be a part of the finale.

Can you tease a little about how Belle is going to feel about what Rumple did, because he did something bad, but he did it in the name of saving their son? Is she going to be a little bit torn about that?

Kitsis: I think she is. I think she's understanding. When you have your kid, sometimes it clouds your judgement. You want to do what's best for them... Belle and Rumple are going to be tested, and everything that they ever wanted is going to be very temptingly close for Rumple. But like everything, it comes with a price.

Once Upon a Time's Season 6 finale airs Sunday, March 14 at 7/6c on ABC.