Peter Jackson’s shadow still looms over New Zealand — just as high as the Eye of Mordor, but certainly more benevolent. This is one of the first things my taxi driver mentions after departing Wellington airport, a quaint port with a massive overhanging sculpture of Gandalf riding an eagle. A “Wellywood” sign — like the Hollywood sign in Los Angeles — catches the sun from atop a nearby hill that overlooks the peninsula, another reminder of the country’s mini film boom that’s due in large part to Jackson’s The Lord of the Rings and The Hobbit trilogies.

It’s here in real-world Middle-earth where Christian Rivers, Jackson’s longtime storyboard artist and visual effects teammate, wants to make his first feature film, Mortal Engines. But establishing himself apart from Jackson’s legacy — a legacy he contributed to — is a challenge of its own.

“My role has always been in service to his vision,” Rivers tells a group of reporters on the film’s set last June. “I mean, that’s what you do. Films are hierarchical and the director is essentially the creative dictator. So, my services to Peter have always been to help him achieve his vision. And now, on this one, it’s sort of the other way around.”

Mortal Engines, based on the book series by Philip Reeves, envisions a post-post-apocalypse of sorts. It’s a desolate world where some of the major cities have been given wheels and transformed into mobile Traction Cities. They now roam the land, devouring smaller cities and stripping them for parts. This all lays the backdrop for what’s happening in the Traction City of London. The young Lower Tier worker Tom Natsworthy (Robert Sheehan) has a chance encounter with a mysterious fugitive named Hester Shaw (Hera Hilmar), and the two are propelled down a path towards uncovering a dangerous conspiracy from within.

If you haven’t been paying close attention, you might think Mortal Engines is a Peter Jackson movie. The Hobbit helmer’s Facebook page has been the primary source of information on this project, and the trailer flashes title cards that read, “Peter Jackson presents an epic new saga.” It makes sense from a marketing standpoint: Jackson’s name is enough to draw audiences. But in another, more creative sense, Jackson laid the groundwork for this film adaptation around 2008 at a time when he was hoping to direct it.

Rivers first came aboard Mortal Engines to work on previz during that time, while Jackson and co-writers Fran Walsh and Philippa Boyens worked out the screenplay. Then The Hobbit came along to consume the next five years of their lives. “Coming out of it, we were faced with a situation where the rights to the [Mortal Engines] books, which we’ve had these rights for probably nearly a decade or so, they were due to expire and we had to move fast,” Jackson explains.

Rivers recalls how another director had been brought on, but then “decided to leave the project.” So Jackson then turned to his protégé. “I know he knows stories and I know he knows how to shoot because of the storyboarding he’s been doing for me,” Jackson mentions. “He’s someone that I’ve always wanted to find a way to support somehow into a feature film.”

It worked out for them both: Rivers wanted to move away from directing short films to pursue his love for “genre adventures,” while Jackson now had time for “other scripts, screenplays, and things while Christian [did] all the hard work.” (These “things,” he says, are mostly “New Zealand stories, relatively smallish, that we want to develop.”)

Now, Rivers is the one steering the ship. The freshman director admits, “I’m also absorbing as much as I can in the collaborative way from everyone who is around me.” That includes Jackson. “He’s helping me direct a film rather than the other way around,” Rivers adds. “That sometimes works. Peter, he’ll have a strong opinion about things, but it’ll be very defendable. And if it’s not defendable, he’ll give in to what you want. So, it’s a very healthy and fun and creative process.”

The pair have been working together for about 25 years now. Jackson remembers getting a fan letter from a young student by the name of Christian Rivers “around my first one or two movies.” It was accompanied by “pictures of dragons and all that sort of stuff,” and inquiring about any potential design work. When it came time for 1992’s Braindead (the original title for Dead or Alive), Jackson remembered this moment and hired him.

“He just left school, and I wanted to do storyboards for that movie,” Jackson recalls. “I’d done storyboards before and I can’t really draw, myself, particularly well. So, I thought of Christian and I thought of that fan note and I looked him up.” Rivers would continue crafting storyboards for “virtually every film since then” for Jackson. With Mortal Engines, it’s now as if a family of filmmakers has come together after all these years to support their kid’s first big effort. Jackson says he helped out shooting second unit shots when needed, but it was really Rivers’ show to run.

It helps that Rivers, as he says, shares “a similar sensibility to the world” with Jackson— a world he’s now trying to make unique. The director realizes there was a certain steampunk element to the first Mortal Engines book, but says he didn’t want to make the film “overtly steampunk.” He didn’t want to go full Mad Max, either, because this isn’t your typical “post-apocalyptic dystopia.”

“I kind of just caught on to what would happen if there was a nuclear-esque war or a new weapon that devastated our planet and what would sort of happen to London,” he says. “And what would be left?” Rivers’ son has also been a longtime fan of Reeves’ series, so “if he doesn’t like the film, I can have a long conversation,” he jokes.

If all goes well, Mortal Engines just might also become Rivers’ very own franchise.

The cast and crew we spoke with were hesitant to confirm a sequel, but most were vocal about their desire to continue on. Hugo Weaving, who graced Jackson’s Tolkien-based franchise, says he’s “technically” already signed on for more romps in the Mortal Engines universe, but that he doesn’t know “practically what that means.” Jackson also teases ways this first film sets up others: “Because we know what is going to happen in the future with these books in the story, we’re able to plant little things here and there that will be helpful to us if… should we be so lucky to make more films.”

Rivers doesn’t seem too concerned with looking that far ahead just yet because “the biggest challenge is still to come, which is all the stuff that we have to do with digital effects.”

“We’re still designing the film as we shoot it, and we’re all really excited by what we’ve come up with,” he says in between filming on set. “But, yeah, we have no idea how it’s going to land.”

For as much as he’s involved, Jackson also recognizes this franchise-in-the-making is a vehicle for Rivers. “I have to see if Christian wants to direct some [more films],” he tells us in a separate interview. “That will be up to him. He might go off and do other things. I’d like to direct. I thought I was going to direct. I’d love to direct the last one if we got that far. But, by then, if he’s directing them, I’ll let him decide. We’d produce them for sure. And, obviously, Christian would be having first offer to direct and hopefully he would.”

Mortal Engines drives into theaters this Dec. 14. For more on the film, click here for 47 things I learned on the set and click here to watch the new trailer.