There are good adaptations. There are bad adaptations. And there are adaptations that rip asunder the source material and gleefully devour its corpse.
This is one of the last category.
I might have been able to still enjoy "The Last Airbender" if it had merely had special effects, a horrible script and actors with the charisma of a plank. But director M. Night Shyamalan gets EVERYTHING ELSE wrong too, from the character motivations to bending.
Southern Water Tribe girl Katara and her brother Sokka stumble across a glowing glacier, and find a young Airbender boy inside. Since all the other Airbenders are dead, Katara figures out that Aang is the Avatar -- the master of all four elements, and the only person in the world who can defeat the powerful Fire Nation.
However, the Fire Nation has already found him, in the form of the disgraced Prince Zuko (Dev Patel). Aang, Sokka and Katara set out on a perilous voyage to the North Pole to find a waterbending master. But the malevolent Admiral Zhao -- Zuko's nemesis -- is approaching the North Pole with the Fire Nation navy, with a plan that may destroy them all.
M. Night Shyamalan had a golden opportunity with "The Last Airbender" -- the original cartoon was intelligent, funny, complex and filled with brilliant martial-arts and strong philosophical overtones. So instead he decided to make a movie with NONE of that -- a witless, humorless, simplistic stumbling behemoth of a film.
The culture, the characters, the climactic battle, the bending, the acting, the action sequences, and even the pronunciation of the names... EVERYTHING IS WRONG. WRONG, WRONG, WRONG. But if I listed everything wrong with the movie, this review would be the size of a novel.
Even from an objective perspective, this movie is a disaster. Shyamalan clearly has no idea how to write an action movie, blasting through incoherent fight scenes in one long pan. The story feels painfully repetitive (how many times is Aang going to be captured?!) and the script is horrendously pompous, humorless and rushed ("We have to show them that we believe in our beliefs as much as they believe in theirs" -- WHAT? You're not trying to SAVE THE WORLD?).
Also, there are gaping plot holes that a three-year-old can spot. So the Fire Nation imprisons Earthbenders, who manipulate rocks and soil... in a friggin' MINE. And the pseudo-Buddhist Aang apparently has no problem with COLD-BLOODEDLY KILLING HUNDREDS OF PEOPLE. Was Shyamalan mocking us with how bad he could make this, or did he just not care?
I will give Dev Patel credit -- even though his Zuko's main source of angst seems to be a mild case of eczema, he does put a lot of passion and intensity into the role.
Sadly, the same cannot be said of the other actors. Aang is wooden and mopey, Katara is weepy and inept, and Sokka comes across as a ticking time bomb. Even the talented Shaun Toub plays the horrendously-written role of Iroh with an air of boredom -- he always looks like he's thinking, "Okay, when do I get paid?" Only Aasif Mandvi seems to be having fun chewing the scenery.
M. Night Shyamalan managed something truly impressive in "The Last Airbender" -- he managed to take a funny, well-written, intelligent series and suck out all the humor, cleverness and likability from it.