Sankaku (2010)

Momose (played by Sousuke Takaoka), who used to be a street punk, lives with girlfriend Kayo (played by Tomoko Tabata). Trouble brews for the couple when Kayo's younger sister Momo (played by Erena Ono) moves into their home for the summer. Momose finds himself gradually being drawn to the free spirited ways of Momo.