Adam Kotsko:

Few genres are as durable as the White Messiah story: a white man shows up in a foreign culture and turns out to be better than the natives at whatever their specialty is, or the only person who can save them, or (preferably) both. Think of Karate Kid or, more recently, Avatar or the Christopher Nolan Batman films. Even Alice in Wonderland has been recast as a messianic narrative of this kind.