Anime: Onee-chan ga Kita
The story revolves around Tomoya Mizuhara, a 13-year-old boy who suddenly gains a big sister when his father remarries. 17-year-old Ichika is a little strange, and her affection for Tomoya is rather overwhelming, if not scary. On top of things, Ichikas friend Ruri is the ultimate sadist. Then there is Ichikas big-breasted quarter-Japanese friend Marina.