(and surely a hundred other movies)
-Guy
-Guy is sent by his team to infiltrate the bad guys while in disguise
-Guy has a thing for one of the girl bad guys
-Some of the bad guys are suspicious of Guy, and he has to prove himself to them despite the efforts of a bad guy who is also a Rival
-Big climactic sequence and Guy sides against his former team, saving his rival in the process (I don't know if this happens in Avatar but it probably will)
-Movie is **** but spawns big-budget sequels
-Guy
-Guy is sent by his team to infiltrate the bad guys while in disguise
-Guy has a thing for one of the girl bad guys
-Some of the bad guys are suspicious of Guy, and he has to prove himself to them despite the efforts of a bad guy who is also a Rival
-Big climactic sequence and Guy sides against his former team, saving his rival in the process (I don't know if this happens in Avatar but it probably will)
-Movie is **** but spawns big-budget sequels