“Once Upon a Time” is kicking off season four with a dose of “Frozen,” transporting the beloved characters of the blockbuster Disney movie to the town of Storybrooke. Ahead of the Sept. 28 premiere, Variety talked to showrunners Adam Horowitz and Edward Kitsis to preview Anna (Elizabeth Lail) and Elsa’s (Georgina Haig) “Once” debut and find out what’s ahead for the rest of the fantasy show’s ensemble.

How will Snow White (Ginnifer Goodwin) and Prince Charming (Josh Dallas) adjust to a second chance at raising a child? Will Emma (Jennifer Morrison) and Captain Hook (Colin O’Donoghue) be able to maintain a relationship despite their differences (and similarities)? How will Belle (Emilie de Ravin) react when she realizes that Rumplestiltskin (Robert Carlyle) is keeping another secret from her? What will Regina (Lana Parrilla) do now that Robin Hood’s (‎Sean Maguire) lost love Marian (Christie Laing) has returned? Read on to find out.

Entering the fourth season, what is your major goal for this year?

Adam Horowitz: I think our goal is to continue to try to get better and improve and to raise the bar on the show. We feel a responsibility to the fans who’ve been with us for so long to make the show as good it can be, to deepen the characters, to explore them. One of the advantages of series television is, the longer you’re on the air, the more you get dig deep into the characters and that’s what we’re hoping to do this year. We left off last season in a place where a lot of our characters were in new situations, and we’re excited to delve into that.

What is the central theme of the first half of the season?

Eddy Kitsis: The first half of the season for us is “never give up on the people you love.”

You attempted a spinoff last season with “Once Upon a Time in Wonderland,” which [ABC President] Paul Lee admitted he probably shouldn’t have rushed to get on the air in the fall when it was initially planned for winter, and subsequently it didn’t connect with viewers the way “Once” did. Would you hesitate to embark on another spinoff series or are you still open to ideas if they present themselves?

Horowitz: We would never say never, and I think that there are lessons learned from “Wonderland,” particularly as Paul said, and I think we all agree, if we were ever to do it again, I think the way to do it is in the middle, after the 11th episode of “Once.”

Kitsis: For us, that was always what we wanted to do and everyone was really excited about the pilot. But of course, looking back I think our audience was watching “Once” at the time and as we say, it’s hard to get a solo album when the band also has an album out that week too. Would we embark on it again? If we had the right idea… This year we felt like we really just wanted to focus on “Once,” but next year, you never know.

How integral are the “Frozen” characters to the first half of the season? Is it comparable to the addition of the Peter Pan arc or the Wicked Witch?

Kitsis: Absolutely. The first half of this season will be “Frozen,” and that will be the arc. It’s the characters from “Frozen” coming into “Once Upon A Time.”

Horowitz: It’s not us doing “Frozen,” the sequel, as a TV show. Instead, it is taking the characters from “Frozen” and bringing them into the “Once” world, as you said, much in the way that we brought the Wicked Witch or Peter Pan, and finding the hopefully surprising way they intertwine with our characters and our mythology.

Unlike most of your characters, “Frozen” is an ongoing property — are you guys tying anything in with Disney’s wider plan for the characters? Is there anything you’re introducing that could be carried over to other iterations?

Kitsis: Nothing we’re doing is canon into the “Frozen” franchise. As Adam said, we’re not doing the sequel. This is us taking Elsa and Anna and Kristoff and just a few of the characters, and they’re coming into our world, and so we’re much more interested in crosses like Anna when she meets Rumplestiltskin and things like that. But all the things that are on our show are not canon.

Horowitz: It’s kind of like how we’ve dealt with all of our characters. The original “Snow White” movie still exists. The original “Cinderella” still exists. We sort of like to think of “Once Upon a Time” as a Disney cul de sac, where you can come in, you can play with these characters, you can see them in new fun ways, and then when you’re done, you can leave and go back and they’re right where they were.

Emma and Elsa have a lot in common as characters, in terms of their familial struggles and their inability to control their powers…

Kitsis: What you just said is exactly one of the inspirations and why we were really excited and asked Disney if we could do “Frozen,” because we looked up at that screen and said, ‘oh, that’s Emma’s bestie.’ They have so much in common and we just loved it, and so we really wanted to explore that because these are two people who really feel alienated, who aren’t sure about themselves, and who have dealt with a lot of pain growing up, and are still coming into who they are as people. That’s what we really loved about it, and we were inspired to say, ‘what happens when Emma and Elsa have a heart-to-heart?’

Can you tease anything else about their dynamic and what they might be able to teach each other?

Horowitz: Elsa has been down many of the same paths that Emma has either been down or is going down, and because of that, they’re going to find a way to bond and a way to work together.

Kitsis: And in the movie “Frozen,” we saw Anna help Elsa come to a realization and give her some advice, and I think what’s fun about “Frozen” and our arc this year is, you’re going to see Elsa doing that for Emma.

Hook and Emma are both very independent characters — what can you say about how they might navigate their new relationship and those personality clashes?

Kitsis: It is an interesting thing because Emma has had some very tough relationships in the past. She’s a very guarded person. We know she puts her walls up to defend herself. So we really wanted to explore it in a real way. Just because they kissed at the end of the season, doesn’t mean they’re registering at Pottery Barn right now. And they’re going to have other things [to deal with] and one of the things that we’re really excited about is, we’re definitely going to show their relationship, but at the same time, we’re going to see Emma continue to evolve and question certain things about herself. And at the same time, we can’t forget Captain Hook was a pirate and he had a very, very unhealthy rivalry with Rumplestiltskin. That, unfortunately [for him], is going to rear its head, but fortunately for us, because it’s awesome. We’re excited to see those two get it on again.

How much will we see Emma struggling with seeing Snow White and Prince Charming being parents after missing out on her own childhood with them?

Horowitz: That’s something that we intend to explore this season, which is Snow and Charming being parents and with a child. They have been parents before but they have thrown that child into a wardrobe. [Laughs.] This is the first time that they’re actually raising a baby. And Emma is witnessing that and she’s also realizing that this is something she’s missed out on and that there is some complexity between all these characters — which is a beautiful thing, having a new child and an expanded family — but there’s issues that are brought out of this.

Kitsis: I think if you asked Emma at the end of last year ‘how do you feel about your parents having a baby?’ she would say, ‘that’s fantastic.’ You’re like… ‘well, why would I be jealous? Why would I care?’ But then seeing your mom get to cradle a baby and give them all the things that you didn’t have, it starts bring up things that you never thought were inside yourself. We all have thoughts and feelings and emotions that we aren’t aware of until something triggers them.

Horowitz: It’s one of the things that we’re really excited to explore this season, which is dipping more into Emma’s past, and seeing some of that and how that shaped who she is.

Kitsis: What we’re really excited about is that we’re going to explore an Emma flashback to her days in foster care in episode five.

And how much will Snow and Charming be struggling with both being new parents and, undoubtedly, being reminded of that lost time with Emma?

Kitsis: Snow White is… obviously, she is a new mother and that is going to be fantastic, but we’re going to realize that losing Emma in the past is definitely going to affect her and the way she parents. But also, Emma’s going to have some new responsibilities in town, and as far as Charming, he’s going to continue to be a great dad to Emma. He is going to be an over-protective dad as she goes on a date with Hook, and at the same time, we’re going to see a flashback in episode two of Charming when he was still a shepherd before he met Snow, when he was still on the farm. So we’re excited this year to show a lot of our characters [in the past]. We’re going to see Belle. We’re going to meet her mom. We’re going to see her before she met Rumple. We’re going to see Charming before Snow. And we’re excited for some of these earlier stories that we’ve only hinted at previously but haven’t really explored.

As you mentioned, Emma’s parents have always been somewhat overprotective to overcompensate for their lost time, so how much of a struggle will it be — for Charming in particular — not to interfere in her relationship with Hook?

Horowitz: It will be a challenge. I mean, it’s one of the fun things for to us explore, which is he’s going to have to a parent to both a newborn and a fully-grown child — a fully-grown child who can take care of herself, who is also being wooed by a pirate. That’s a lot for any man to handle.

Another combustible couple are Regina and Robin Hood. Some preview photos from the premiere show Marion looking less than pleased with Robin — is it as happy a reunion between them as people might expect?

Kitsis: It’s a difficult reunion because, obviously for Regina… what we loved about the finale is that before this happened and she was walking into that party, you saw her the happiest she had ever been on the show, even before when she was a teenage girl. So we have three years of evolution for this character. Now she’s faced with her first real emotional setback. Not a plot setback but an emotional one. So for us it was a question of, “how does she deal with it?” The old Regina would immediately rip everyone’s heart out. What will this one do? And Marion is a stranger in a strange land, and it’s one thing that you find out you’ve traveled through time and your husband has moved on, but it’s another thing to find out he moved on with the person who killed you. So it’s going to be uncomfortable over there in the Sherwood Forest part of Storybrooke. [Laughs.]

As you said, this is a huge setback for Regina — how do you balance the central conflict of her dark impulses warring with her journey towards redemption without undoing the last three years of character development?

Horowitz: That’s what’s interesting to us about it. This is not about Regina reverting to being The Evil Queen from season one. She can’t; she’s come too far, but that Evil Queen is a huge part of who she is. So we have a challenge before her that is huge, that is going to require her to wrestle all the different aspects of her personality. Her dark impulses and her light ones.

Kitsis: And another thing that we’re really excited about is, Regina’s story is not just Robin Hood. We have seen Henry in the past with Operation Cobra with Emma, but he is going to be in a new operation with Regina this year that is actually going to [last] the whole year.

On a related note, Rumplestiltskin also has some old habits that die hard — what kind of tensions are we likely to see between him and Belle this season, given that he’s now keeping another secret from her?

Kitsis: I would not want to be him if she finds out that he’s been lying to her. But we’re going to find out in the premiere why he did what he did. Rumple is going to be set upon a new course and he’s a man who has always struggled between power and love, and that is going to still be a factor in his life. And I think that, [between] him and Belle, in that story and what they’re doing, it will be pretty obvious in the premiere what’s going on and what he’s looking for.

You noted that Marion is a stranger in a strange land and obviously, Elsa is too — will we see their paths cross or are they on different story arcs?

Kitsis: They’re kind of on separate story arcs, I would say. They will have some interaction, but they are also on separate story tracks.

Emma bringing back Marion in the finale obviously threw another wrench in her relationship with Regina, but as you said, Regina has also evolved. What can you preview for their dynamic this season?

Kitsis: I think the relationship is tough because Emma decided to save a life, and that life kind of destroyed Regina’s happiness, and so they may have been at it at the top, but one of the things we’re excited to explore is, you know, what does Emma think about Regina? How does she look at her now, and how does Regina look at Emma now? And there’s going to be an entire episode devoted to just that relationship and how they feel about each other.

“Once Upon a Time” season four premieres Sunday, Sept. 28 at 8 p.m. on ABC.