Showrunners Adam Horowitz and Eddy Kitsis talk with THR about what to expect from an adult Henry Mills and that major twist.

[This story contains spoilers from the season six finale of ABC's Once Upon a Time.]

The sixth season of ABC's Once Upon a Time has come to a close and with it the stories of the entire Charming family — at least, this version of them.

After defeating the Black Fairy (Jaime Murray) and rejoicing in their happy endings (which were happy beginnings all along), the book finally closed on Emma Swan (Jennifer Morrison) and her fairy tale.

Leading into Sunday's finale, stars Ginnifer Goodwin, Josh Dallas, Jared Gilmore and Morrison announced their departure from the show, begging the question of how the story will continue without any of its main heroes. As expected, the Disney-inspired fairy tale drama's big time jump at the end of the two-part finale provided the answer. The story now seems as if it will start over from scratch, this time with Henry (The Walking Dead's Andrew J. West, a new series regular) as the adult whose long-lost daughter Lucy (fellow new regular Alison Fernandez) shows up on his doorstep to prompt him into saving his family.

The Hollywood Reporter turned to series creators/showrunners Adam Horowitz and Eddy Kitsis to go inside the decision to overhaul the series, what it means for old characters and why fans should continue to tune in for season seven of Once.

Are you approaching the story of adult Henry as a total reboot of the original Once Upon a Time premise?

Kitsis: Kind of, yeah!

Horowitz: I hesitate to use the word "reboot." We’re more thinking about it as a hybrid of a lot of things. We’re paying homage to the original premise, but there are certain characters who are returning and some who are not. It’s a combination of a lot of things, but what we’re trying to do is go in a new direction but stay true to the spirit of what the show has always been.

Will you be recasting any other characters as adults?

Kitsis: Potentially, yes. Not right away. That’s the biggest one.

Horowitz: We want to keep under wraps how we get to Henry grown up and what that means for Regina (Lana Parrilla) and Hook (Colin O'Donoghue) and Rumple (Robert Carlyle), who are returning regulars. There’s stuff that we’re excited to unveil, but it’s not about recasting so much as we’re hoping to open up the universe more.

How do you plan to tell stories about Regina, Rumple and Hook without some very important family members?

Kitsis: The answer to that question will be answered next year. We’d rather show it than tell it.

Henry’s got a daughter. Will we be meeting her mother?

Kitsis: Yes, next year. [Lucy's] mother and Henry will be a very epic love story in the tradition of Once Upon a Time, just like his grandparents. We can’t forget, he’s the grandchild of Prince Charming, which technically makes him Prince Charming Jr.

Horowitz: Junior junior. Prince Charming III.

How many new roles are you looking to create with six series regulars leaving?

Horowitz: I don’t think we want to confirm exactly right now, but we will say there will be more regulars, and they’ll be more recurring characters as well, and we’ll probably make some announcements as the summer progresses.

Besides Jennifer Morrison, who will return for one episode and who has promised to pop back in?

Kitsis: Everybody has said they’d be willing to come back. As our show is and has been for six years, we see people come back all the time. Rose McIver came back and she is the lead of her own show [The CW's iZombie, which was also renewed], so we hope to be seeing everybody.

Horowitz: While we tried to really wrap up a lot of their stories and give a nice send off to these characters we’ve loved being with for six years, they’re still part of the universe, so hopefully we’ll be seeing different people at different times.

Fans, as would be expected with six regulars leaving, are upset. How do you get them to come back for season seven?

Kitsis: At a certain point after six seasons, some people’s journeys needed to have an endpoint. We believe that what we are going forward and doing is what people love about the show, which is a show about hope and fairytale characters trying to find themselves in the real world. We’re going to return to more storytelling like that, and if they love the original Once, then hopefully they will enjoy the next chapter and the new universes and adult Henry.

Horowitz: We’ve been so blessed to have such an incredibly passionate fan base that feel so strongly about all these characters that we totally hear and feel the emotion at hearing that some of these characters won’t be there every week. But some will and then there’s always chances of seeing some again. But really, I think as Eddy said, we’re trying to go on in the spirit of what we started in season one and telling those kind of stories again with a new canvas that’s really exciting to us as storytellers. We really hope that the audience will feel the same way as they see these new stories that we start to tell.

Kitsis: Part of it really is, creatively, wanting to end one chapter and begin a new one and get back to that fresh, original idea that resonates.

Once did hit a string of series lows in season six. How do you hope to bring new viewers back and broaden the show to those who haven't tuned in before?

Kitsis: You can’t really control ratings. Every year ratings go down and everyone reacts like it’s the first time. I think that though ratings are down, what’s interesting is the fan base continues to be up, so we’ll still trend and all those things. That being said, we feel it’s a great way next year for new viewers to come in and not be burdened with knowing the six years of mythology. You can come in fresh next year, and I think if you like fairytales and you like magic, you should check it out.

Horowitz: The live, next day ratings — we all know they’re becoming more archaic … We’ve been so encouraged that regardless of what numbers are saying, we have an incredible fan base that’s been so passionate all these years. To us, it just feels like a miracle that it’s season seven and we’re working on it. We’re so grateful to the fans who have stuck with us, so that we’re here.

What did you think of the Once Upon a Time season finale? Will you be staying on board for season seven? Sound off in the comments section, below.