The story revolves around Haruki, the second of five siblings, and his four sisters: high schooler Mutsuki, middle schooler Yayoi, and grade schooler twins Uzuki, and Satsuki, who share a multi-unit apartment (danchi). While their life may seem monotonous, aside from the fact that Haruki's sisters don't give him a single opportunity to rest, lecturing him about every perceived mistake and playing tricks on him, Haruki still likes his life.