Thanks to his parents' job transfer, high school freshman Kazunari Usa finally gets to enjoy living on his own in the Kawai Complex, a boarding house that provides meals for its residents. Ritsu, the senpai he admires, also lives in Kawai Complex, as do a few other "unique" individuals: his masochistic roommate Shirosaki; beautiful, big-breasted Mayumi who has no luck in finding men; and sly, predatory college woman Sayaka. Surrounded by these people, Usa never finds his daily life boring. (myanimelist.net)