Oni Tsurugi (voiced by Okubo Rumi) is a tsundere girl with long purple hair and aloof hair. She has a cute and awkward personality and has a lover - Otonashi Imi (voiced by Okamoto Nobuhiko). In Imi's eyes, Tsurugi is a little sister who needs to be taken care of, which makes Tsurugi feel very crazy. Although she is completely unconscious, Imi often makes some stimulating actions that Tsurugi cannot bear. Surrounding this pair of silly couples who are more than friends but less than lovers is a group of interesting and kind friends. The innocent Haruno Hime (voiced by Fukuhara Kaori) is always fooled by the prankster Katase Mayoi (voiced by Namatame Hitomi); and Inui Sakaki (voiced by Asanuma Shintaro) who has a stiffness syndrome always becomes stiff and unable to move when the jokes reach their climax. This group of lovely friends and the daily life around them are the main content of this animation.