Kousuke lives in an old apartment alone since his divorced mother is abroad on business. One day, two transfer girls join his class. Actually, they are his new sisters because his mother gets remarried. His new father is unreliable, and he is an easy prey for swindlers. They are on honeymoon now, and he can't get in contact with them. Also, he finds out that his new father borrows money from his apartment owner, and the owner tries to kick him out. Finally, the owner lets him to pay in installments, and he starts to live with his new sisters. One day, he falls in love with a girl....