Tekkonkinkreet (Black and White) torrent

Two orphan brothers the tough, canny Kuro and the childish, snot-nosed Shiro who live in the streets of Treasure City. Together they are known as Neko and they live homeless, living out of a car in the junkyard when not visiting Gramps, an older homeless man, these children also serve as the city's superhero guardians, although older brother Black must also give a great deal of personal attention to White, who even for a ten-year-old can sometimes seem very disconnected from reality. They're going to have to be on the top of their games, because a pair of Yakuza - Rat and Kimura - are returning to Treasure Town, but to a certain extent their only front men for a group of developers looking to build a family amusement center - and they've hired the monstrous looking Snake and his inhumanly powerful goons to make sure it gets done.

imdb: http://www.imdb.com/title/tt0831888/