Avatar is a 2009 American science fiction epic film written and directed by James Cameron and starring Sam Worthington, Zoe Saldana, Sigourney Weaver, Michelle Rodriguez and Stephen Lang. The film is set in the year 2154, when humans are mining a precious mineral called unobtanium on Pandora, a lush moon in Alpha Centauri. The expansion of the mining colony threatens the continued existence of a local tribe of Na'vi—a sentient humanoid species indigenous to Pandora. The film's title refers to the genetically engineered Na'vi bodies used by several human characters to interact with the natives of Pandora.