I, Tachibana Mako have a twin sister named Tachibana Koma. She’s different from the hopeless me who can’t do anything, she’s kind, beautiful and brilliant and a little sister who I am proud of. But, there’s one thing that I can’t talk to anybody about my little sister. This is the beginning of a silly yuri (?) rom-com about an enthusiastic siscon elder sister and her lovable younger sister!