It's been 13 years since James Cameron's Avatar beat his previous blockbuster, Titanic, to become the highest grossing film ever released. But now at long last he has returned to the jungle moon of Pandora - and roughly 13 years have passed there, too. Jake Sully (Sam Worthington), his mind now permanently installed in a blue alien Na'vi body, is the chief of his clan, and he and his wife Neytiri (Zoe Saldaña) have four children. They spend their time lolling around in skimpy loincloths, thinking about how happy they are, but inevitably their Edenic and slightly risqué tranquility ends...