Super Citizen.

A young man from the country comes to Taipei to search for his sister from whom he has heard nothing during the past year. Beginning in a tenement slum, the young man travels through the city's lowlife, where street hustlers sell fake Rolex watches and other contraband, gangs fight each other, and the ubiquitous sex businesses ply their trade. The young man befriends a rich teenage girl and a young prostitute as he and a hustler who knew his sister search for her through a trail of clues leading to restaurants, dance joints, and brothels.