DIVIDE ディバイド (2006)

Saki's life is thrown into chaos when her mother drops dead. She then finds herself joining an evil crowd, the high school pimp and his rogues who become her social life. Her friends no longer recognize her, and all she lives for is to find the sister she was separated from at a very young age. The vicious sex and violence will all be worth it, if only she can find the sibling she never knew.