Now this is what you do with Roar Uthaug. After he makes one of the best Hollywood disaster movies in recent history in The Wave, with its love of the genre firmly and unapologetically on its sleeve, you don't bring him to Hollywood, give him a mid-budget also-ran reboot of a character that was never very interesting anyway and let marketing and development executives stamp every shred of creativity or directorial vision out of it, like they did with that ill-advised Tomb Raider go round starring Alicia Vikander.

You send him home to Norway, give him what's probably a tiny budget by Hollywood standards but which buys very good production design and VFX in his native Scandinavia, and let the relevant film funding body welcome him with open arms, giving him access to the city and countryside around Oslo, closing streets for filming and giving him all the help he needed.

Because, like The Wave, Uthaug proves he's one of the best directors of big idea disaster action in the business today. He's like a leaner, more precise Roland Emmerich – Troll has none of the bloat of the flicks Emmerich made in America, and Uthaug still manages to squeeze in some throwaway comedy and cute characterisations.

It's also not just a cool movie about the idea, it perfectly melds a story about a very established piece of folklore in the modern and contemporary world, like Chris Nolan did with Batman Begins.

When a mythical creature attacks, politicians and military strategists meet in coolly coloured conference rooms and operations centres and soldiers drive up in camo gear and tanks, brandishing automatic weapons and rocket launchers to fight it.

Nora Tidemann (Ine Marie Wilmann) is a young teen when we meet her, sitting in one of Norway's breathtaking mountain ranges while her Dad teaches her about the history of real life trolls, and when she sees a rock face across the valley seem to move, as if an enormous head is turning to look at her, Nora is convinced.

Decades later, she's a far more practical and cynical palaeontologist digging up dinosaur bones on the coast, the time and funding on her and her team's current project running out.

But with the arrival of an army helicopter, Nora is called away to a far more urgent matter. During a drilling operation in a mountain range in the wilderness, a gigantic roar has rung out from deep underground and something enormous has burst out of the ground, killing workers and placard-wielding protesters nearby alike.

Nora is whisked to a secret government office where she joins an array of other advisors, top military and political leaders right up to including the Norwegian Prime Minister. Something has emerged from underground, and the only clue is the gigantic footprints leading away from the site. It's Nora who wonders – when a video from the incident comes in – whether she's actually looking at a giant face.

The Prime Minister assigns Nora to take her advisor, Andreas (Kim Falck) and a solider, Kris (Mads Sjøgård Pettersen) to the site and try to figure out what's going on, the rest of the harried delegation arguing about everything from methane pockets to seismic activity.

As the three arrive by helicopter and look around, an elderly couple in a faraway village hear rhythmic booms approaching, getting closer and louder until crockery and furniture is rattling and falling over. They bustle themselves into the storm cellar and Uthaug stays inside with them as something massive and destructive passes overhead, their house demolished when they finally emerge.

Nora, Andreas and Kris recruit Nora's father, who we learn is now a crazy conspiracy theorist and recluse when she has no choice but to seek him out for his help. They're getting weird readings near a rock formation – as well as a strange smell they suddenly detect – when a huge, angry eye opens on the rock and they run for their lives as the creature stands to its full 150 metre height.

Nora's father was right, as he always claimed. Trolls are real and used to roam the mountains of Norway a thousand years ago, but in the modern age of political motorcades, fighter jets on standby and one government minister joking about King Kong, they've just been forgotten. And the proof is right there in front of Nora and the gang in terrifying detail.

As the creature advances across the country, laying waste to small villages and heading for Oslo, the government scrambles to respond, sending fleets of attack choppers, every weapon they have and having to admit there's an unacknowledged missile that's obviously nuclear but might be all there is to stop the huge, bearded monster made of rock.

The military plan is in motion, one Nora and the rest of her gang knows is a terrible idea, so as the creature arrives in the now-evacuated capital the race is on to get there in time to figure out how to stop it.

It involves the truth about the myth, one that leads them to Oslo's Royal Palace and reveals a shocking past, and a plan to trap the creature in a park surrounded by UV light generators – as everyone also knows about trolls, they turn to stone in sunlight.

Uthaug's script and direction so cleverly and so simply takes two elements you can't imagining fitting together – the folklore of trolls, intact and without embellishment, and the trappings of a modern developed country in the throes of a national defence emergency – and melds them perfectly.

He delivers every element with utter perfection. In just one example, Uthaug reveals the monster at exactly the right time and in spectacular fashion – far enough into the running time to both give you a great and realistic set-up and build anticipation, but with that anticipation not overstaying its welcome by a millisecond.

His script also doesn't reinvent the lore – the reason trolls went underground was because Norway became a Christian country, and as the nursery rhyme wisdom has it, they hate the smell of Christian blood. Hi situates such fairytale elements seamlessly in a modern action thriller containing all the usual trappings that come with it.

The actors and dialogue do exactly what the story demands, and seamless VFX provides several very satisfying money shots. There are a few themes (nature fighting back against mankind) beneath the surface that give it just enough deeper context but it's just great fun, like something Irwin Allen would have made at his peak if he'd had CGI.