As black smoke spews into the blue sky, two humongous mobile cities careen wildly and at furious speed across the land. Their fat wheels groan under their bulk and deep trenches scar the barren ground in their wake. The hunt is very much on, but the result is inevitable. Massive grappling hooks shoot out, grabbing the smaller city and pulling it into the belly of the bigger beast. It's less survival of the fittest and more might is right.

This is the clanging, rumbling world of Mortal Engines, the upcoming Christmas blockbuster from Sir Peter Jackson. The movie's first full-length trailer released today, and as well as those mind-boggling machines, also features assassinations, stabbings, angry mobs, fantastical aeroplanes, a hint of romance and a sneeringly villainous Hugo Weaving.

"It's always exciting to release a trailer and let everyone know what you're doing," Jackson tells the Herald, before detailing a packed schedule that involves editing, music recording and visual effects meetings. "We almost don't get a chance to bask in the moment because everything else is sweeping us along."

Jackson and his regular writing partners Fran Walsh and Philippa Boyens have adapted Mortal Engines from British author Philip Reeve's series of novels. This is recognisable practice to those familiar with Jackson's work, however this time there's one big difference; Jackson isn't directing. Instead, as producer, he's tapped longtime protege Christian Rivers to helm.

Hera Hilmar stars as Hester Shaw in Peter Jackson's upcoming movie, Mortal Engines.
Hera Hilmar stars as Hester Shaw in Peter Jackson's upcoming movie, Mortal Engines.

"I was intending to direct but then The Hobbit came along," Jackson explains. "I've worked with Christian for 25 years and I just thought it would be great to give him a chance to shoot it."

A $100 million, special effects extravaganza is a helluva directorial debut for Rivers who has been with Jackson ever since finishing school and storyboarding 1992's cult splatter flick Brain Dead. More recently he did second unit work on The Hobbit and Disney's Pete's Dragon, and made his own short film Feeder.

"There was no way I was gonna say no, but it was terrifying," Rivers says. "I did have to take a breath and think about it. I was well aware of what a huge challenge it was going to be. But that's why we're in the business of making movies like this. Taking those challenges and putting them on screen is hard work but it's also the fun part."

Mortal Engines is a long-held passion project for Jackson, who snaffled up the movie rights about a decade ago.

"I read books that sound intriguing and interesting but the vast majority of the time I don't charge out and buy the film rights. I just enjoy it and move on," he says. "But what I always go on is if I read a book and say, 'I'd love to see this film'. The easiest way for me to see it is to buy the rights and make it. That sounds simplistic but that's actually pretty much how it works."

What wasn't so simple was translating the book's rumbling and mobile "Traction Cities", to the big screen.

Film-maker delighted to lift the covers off trailer for sci-fi passion project. Photo / Shutterstock
Film-maker delighted to lift the covers off trailer for sci-fi passion project. Photo / Shutterstock

"It's hard to wrap your head around sometimes," Jackson admits. "There's nothing in the world you can compare them to. They're not like an aircraft carrier or a cruise ship. They're way, way bigger than that. London is a mile and a half long and three-quarters of a mile high."

Geography buffs will spot London landmarks Big Ben and St Paul's Cathedral perched on top as London speeds past, lending some familiarity to the movie's wonderfully unusual, futuristic concept.

These are the "visual treats" of the story but Jackson says, "the story isn't about moving cities, it's about the societies on the moving cities and the characters in those societies. I've never, ever seen a movie remotely resembling this, or this world, or seen characters like this before."

The trailer is fast-paced and action-packed. It excites and leaves you hungry for more. I tell them I broke my "no trailers" policy to watch it before talking to them.

"Don't worry Karl," reassures Jackson, "there's lots and lots of cool things in the movie that you didn't see in the trailer. I'm with you on the trailer idea. But this trailer doesn't spoil the film. I promise you."