Haruki Nakano leads a typical high school life, with the exception that his mother is abroad and he shares an apartment with his four sisters. There is the eldest, Mutsuki, who has the bad habit of falling asleep in his bed; the junior high school student Yayoi, who hits him whenever something happens; and the grade school twins, Uzuki and Satsuki, who love playing pranks on their older brother. Trapped in a house with four girls, Haruki must cope with all sorts of trials. From grocery shopping and watching scary movies to kissing practice, life is never boring in Danchigai!