Jennifer Morrison

Get ready for a timey-wimey adventure when Once Upon a Time heads back to the past during the epic two-hour season finale on Sunday (8/7c, ABC).

When Emma (Jennifer Morrison) and Hook (Colin O'Donoghue) are sucked into Zelena's (Rebecca Mader) time portal, they'll find themselves in the Enchanted Forest that was. Of course, in true time-traveling fashion, their very presence and anything they do could disrupt the future, and that includes changing the course of their own lives.

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How will Emma and Hook get back to the present? Maybe the Savior could slip on a pair of those silver slippers, click her heels and say, "There's no place like home." Unfortunately, it won't be that easy since Emma doesn't know where home is. TVGuide.com turned to executive producers Adam Horowitz and Edward Kitsis to get the scoop on the two-hour finale, including who's returning, where Season 4 will take the group and whether Zelena is really dead:

Emma and Hook are going to end up in the past in the finale. Could they affect the future?

Edward Kitsis: Absolutely. The biggest threat they're going to face in these two hours is not ruining their past.

Adam Horowitz: They've got to figure out a lot of things, not the least of which is getting home, but also how to make sure there's a home to get home to.

Is there a part of Emma that grapples with whether or not she could change things and end up being raised by her family?

Horowitz: There's a part of Emma that is certainly going to grapple with what her family is like in the present and the past and what that means for her, because there's a very good chance she's going to get to see what things were like before her parents were her parents.

Kitsis: At the beginning of the year in Neverland, we set up that Emma said to her mom Snow White (Ginnifer Goodwin), "I still feel like an orphan." Then we saw that her happiest time in life is a fake memory that Regina (Lana Parrilla) gave her, which was New York. She's trying to get back to that with Henry (Jared Gilmore). She's rejecting her life. Emma is a character that's looking for home, but because she's never had one, she doesn't know what it is. These two hours are really going to answer that question, which is why it's titled "There's No Place Like Home."

Fans are worried that Emma and Hook could accidentally erase the last three years of the show. Do you want to defend yourself?

Horowitz: First of all, I would say that we're not going to defend anything before it has actually aired. Let the fans watch it and then we'll talk after. We are very excited about our storytelling choices and we think we're doing something that is uniquely our show.

Kitsis: And satisfying. They can worry all they want, but they should hold off until Sunday night.

Horowitz: Put the pitchforks away, watch the show and then we'll talk.

When you first envisioned the pilot, you guys considered killing off Charming (Josh Dallas), but then feared you would rob Snow White of her happy ending. What does that mean for Emma when it comes to her happy ending? That it isn't about love for her?

Kitsis: What we said in Episode 11 this year, "Going Home," which was the winter finale, is that happy endings aren't always what we think they are. That is an important thing because at the end of the day, our show at its core is about hope. That is, in a lot of ways, what the theme of the season is, that happy endings aren't always what we think they are.

Horowitz: Happy endings aren't always about other people. They're not about whether you're going to wind up with this person or that person. Happy endings are about yourself. The show has been about Emma's journey over three seasons so far; about who she is, who she was and who she's going to become.

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Did Zelena really die or is there a chance that she could be brought back to life because of the time traveling?

Kitsis: She was definitely defeated. It definitely looks as if she's dead and she will not really be in the finale. That being said, we didn't find a body, so we'll see whether or not she can resurface in the future.

What is the rest of the gang dealing with in present-day Storybrooke?

Horowitz: There's a lot going on in present-day Storybrooke.

Kitsis: We've got the Rumple (Robert Carlyle) and Belle (Emilie de Ravin) proposal.

Horowitz: They're registering at Crate & Barrel. In all seriousness, we saw that, as far as everybody is concerned, Zelena is in a jail cell, but she's not. Now she's dead. That's a piece of the puzzle that is going to very quickly become apparent to everyone. What are the effects of that? There's also the matter of a baby without a name. There are plenty of things for our characters in Storybrooke to be dealing with.

Kitsis: And Doc (David Paul Grove) has to see how long it will take for his Miata to get fixed. [Laughs]

Will Belle discover that Rumple deceived her?

Kitsis: We've learned on this show that secrets tend to really come back and bite you, but whether or not it's in these final two hours remains to be seen. I'll tell you this: Rumple's proposal and his love for Belle is genuine, but he's a complicated man. He's told us he's a difficult man to love. We're just beginning to explore what is going on in his head. A lot of that will be revealed next season.

What should we divine from that smirk on Regina's face after she locked up Zelena's pendant in her vault?

Kitsis: It's funny that you bring that up. That's one of my favorite scenes in that episode and maybe the series. What that smirk said was: I won and I like myself today. She used light magic. She went against somebody she didn't think she could beat. She has Robin Hood (Sean Maguire) and she is making huge strides toward a new life. We wanted to show you a private moment where Regina — who really cast the curse because she felt like she could never win and never find happiness — in that moment alone, she smiles and says, "I won."

Some fans worried that it meant she might've been conspiring with Rumple.

Kitsis: No, that was a genuine moment. It's hard when you have a show like this because we love to give surprises and twists, but sometimes people read into our genuine moments. Really, she won and she's happy. Let's enjoy that for her.

We've been waiting for a big wedding in the finale. Everyone has been expecting that it's Rumple and Belle's, but could it actually be Snow and Charming's wedding from the past?

Horowitz: It could be your wedding!

Kitsis: They're going to your wedding on the show and we are going into the future. [Laughs] RumpBelle fans, we will definitely explore them in our next chapter. As for what wedding we have, watch it live on Sunday.

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Will we see any surprise guests returning for the finale?

Horowitz: Maybe.

Kitsis: We're going to see a good group of the people that we've come to know. Of course there are some faces we wish we could see that we won't. And there will be some faces that we forgot about that are coming back that we'll be excited to see. We are definitely going to tell you whether or not Aurora (Sarah Bolger) was killed as a monkey or she's alive and everyone is good.

Will the finale offer up a hint as to who the villain will be for Season 4?

Kitsis: We're definitely setting up the area into which we are going next year. You will know what we are planning to do at the end of these two hours.

Once Upon a Time's two-hour season finale airs Sunday at 8/7c on ABC. Watch a sneak peek here.