Air, Water, Earth, Fire. Four nations tied by destiny when a Fire Nation launches a brutal war against the others. A century has passed with no hope in sight to change the path of this destruction. Caught between combat and courage, Aang (Noah Ringer) discovers he is the lone Avatar with the power to manipulate all four elements. Aang teams with Katara (Nicola Peltz), a Waterbender, and her brother, Sokka (Jackson Rathbone), to restore balance to their war-torn world.

3D mess typifies how far Shyamalan has fallen.

Few filmmakers have seen such a seismic shift in film-goers goodwill as M. Night Shyamalan. Only a decade ago, he was the poster boy for smart Hollywood blockbusters after the enormous success of The Sixth Sense (1999); he wobbled slightly with Unbreakable (2000, though it has gone on to achieve a huge cult following), then bounced back artistically and commercially with his most finely-constructed film to-date, Signs (2002). But he pissed off a lot of people with The Village (2004) and the ambitious but murky Lady in the Water (2006), and truly bottomed-out with The Happening (2008), his compellingly awful eco-horror dud.

So his adaptation of the popular animated series Avatar: The Last Airbender (the 'Avatar’ has been dropped for obvious reasons) comes at an intriguing point in his career trajectory. He needed a big hit, so securing a potential franchise-starter was a good move (and it seems to have worked, with the film tipping the US box office scales at a not-inconsiderable US$132million). But the sweeping fantasy adventure is very different to the intimate A-grade B movies that made Shyamalan a household name – has he sold-out his patented twist-in-the-tail character-driven genre films in the name of a big-budgeted professional resurrection project?

The elements of the planet – Air, Earth, Fire and Water – are now four kingdoms united in peace by the ruling Airbenders. These chosen ones can control all elements and, as such, ensure balance and peace. When the last of the Airbenders, Aang (Noah Ringer), disappears, the Fire Nation rises in defiance of the spirit of co-existence and sets out to dominate the world. A century of feuding passes before two teenage Water nomads, Katara (Nicola Peltz) and Sokka (Jackson Rathbone), discover the entombed Aang. They journey with him to the north, where he learns the way of the Water Tribe and prepares the disparate clans for the ultimate battle against the marauding Fire Tribe, led by Lord Ozai (Cliff Curtis), his cruel son Prince Zuko (Dev Patel) and his simpering offsider, Commander Zhao (Aasif Mandvi).

The Last Airbender has a conceptually grand scale in its design and a series of strong character beats in its narrative arcs that should make for a quality summer blockbuster.

With a tremendous debt owed to his special effects team and the keen eye for grandeur of cinematographer Andrew Lesnie (the Lord of the Rings trilogy), Shyamalan gets the 'sweeping fantasy’ parts of his film right. Much-loved characters from the animated series are brought to life, including the monkey Momo and a flying bison named Appa (who looks terrific but is a little too reminiscent of the luckdragon Falcor from Wolfgang Petersen’s The NeverEnding Story, 1984). Epic battle scenes, martial arts acrobatics and manipulation of the fire and water elements are all entirely convincing; the post-production 3D makeover is not.

But it is in writer/director Shyamalan’s dialogue that the film grinds to a halt. His words have grown increasingly pompous and stilted since his concise, crisp, Oscar-nominated script for The Sixth Sense; it’s hard to believe that the same man who penned the iconic 'I see dead people" line could unleash such straight-faced howlers as 'Some great monks can meditate for four days!" The young cast of The Last Airbender are called upon to deliver their line-readings as if their lives and not those of their characters depended upon it; rarely has a film full of pretty, agile young people seemed so stilted and morose. The worst of the film’s characterisations, though, are the villains – for a man with ambitions to rule the world, New Zealander Cliff Curtis imbues his 'Lord Ozai’ with a determined air of 'eh, whatever’; Slumdog Millionaire’s Dev Patel plays Zuko as petulant and wimpy; the mega-miscasting of The Daily Show’s high-pitched funnyman Aasif Mandvi as military leader Zhao is a corker.

Shyamalan has often cited his adoration for Steven Spielberg and of the influence of the great filmmaker on his formative years. The Last Airbender features many of the indicators that exemplify Spielberg’s oeuvre – a young boy in the lead role, a vast canvas upon which to explore personal themes, existential dilemmas within a fantasy setting. The end result, sadly, only typifies how far from the assuredness of Spielberg’s best the last few films from Shyamalan really are – none moreso than The Last Airbender.