Avatar is a screenplay by James Cameron.
Earth is dying. Plagued by more than 20 billion humans who have destroyed its ecosystem, the Earth will cease oxygenating the atmosphere in less than three centuries. The oceans are dead - made lifeless and toxic by centuries of abuse. Mankind survives through technology alone: genetically engineered plants and fungi keep us on the brink of starvation and extinction.
Hoping for miracles, a group known as the Consortium, backed by manufacturing heavyweights, operates an ambitious long-distance colony project to our neighbour solar system, Alpha Centauri. There, orbiting the gas giant Prometheus, is Pandora, an M class alien world ripe for the plundering.
A strange metal energised by the magnetic feilds of Prometheus is the principal object of the Consortium's foray into deep space mining: this superconductor promises to revolutionise computing and space travel (while netting their backers trillions, of course.)
The problem is the planet. Its atmosphere is toxic hydrogen cyanide, for a start. But the plant an animal life is totally alien, and highly dangerous. A native pathogen has killed off the human cold and flu strains that the colonists have brought with them, and this 'cure' is currently being pushed through the FDA for approval in a year - a wonder drug like this is a tasty spin-off for the Consortium. But the forest is full of very nasty critters: plants and animals that could kill a human in an instant: each of them is beautiful, but deadly.
There is an aboriginal population as well: the Na'avi, a peaceful, nomadic society of catlike humanoids. They have an advanced spoken language and posess a great deal of knowlege about the world and its animal and vegetable inhabitants. They're vital to the Consortium as well, as they will be the slave labour that will build their factories. (It costs a lot to run the colony, and the Consortium doesnt want to fork out to send thousands of workers and tons of equipment).
Fortunately for everyone, the Na'avi happen to be genetically compatible with humans. Human genetic engineers combine their genome with our own, creating a hybrid. Here's the interesting part: they take the genes of a living person (called a Controller) and combine them with Na'avi genetics to create the hybrid, which is called an Avatar. The hybrids are implanted with some kind of biological control chip. Then, the Controller 'rides' the Avatar's body from a distance via a Psionic link. It is hoped that the Avatars will serve as the means for the Consortium to turn the Na'avi into a slave society to build their factories.
Set within this richly detailed world, James Cameron's story follows the tale of a paralysed, ex-Marine Controller who is thrown into the mix as he hasnt been training for years - he is picked up in a mix-up between him and his twin brother. Josh treats his real life as a dream and his life as his Avatar becomes his waking existence. As he grows closer to the forest and the Na'avi he forgets his human life, and the ineveitable confrontation between him, his Na'avi family and the Consortium looms just out of view...
James Cameron has talked about Avatar in numerous interviews. He envisages it using CGI actors, Gollum-style - and says he needs $300 million to make it a reality.