Jake Sully (Sam Worthington), a paraplegic Marine, is offered the opportunity to travel to Pandora, a distant planet that Humans are mining for precious minerals.
Once on Pandora Jake is told that the marine objective on the planet is to relocate the local indigenous population, the Na'vi, tall blue cat-like creatures, as their villiage rests on the richest source of minerals.
Jake learns that he is to inflitrate the Na'vi by having his conscious projected into an Avatar - a Na'vi/Human hybrid grown in a lab using his DNA. If he completes his mission, the scientists will give him back his legs.
Ported into the Avatar, Jake takes full advantage of the freedoms his new body provides, and quickly crosses paths with the Na'vi, in particular, the beautiful Neytiri (Zoe Saldana).
With the pressure mounting to move the Na'vi, the Marines mount a final charge determined to exterminate the whole population, but Jake has a change of heart.
Realising he has finally found something worth fighting for, he joins with the Na'vi and leads them against his former employers, utilising the creatures and enviornments of Pandora to fight off the superior Marine invasion.