Ino Sakura has recently moved to Tokyo to join Fruit Tart, a newly formed idol group that includes three other members: Roko Sekino, a former child actor; Hayu Nukui, an unsuccessful musician; and Nina Maehara, a model still awaiting her first job. They quickly start their new life together in their dormitory, known as the Mouse House. However, there is no time to settle in, as the girls wake up to a shocking truth: Fruit Tart is already in debt of one hundred million yen and has not even begun its activities! Faced with the possibility that Fruit Tart will disband and the Mouse House will be demolished if they fail to repay the debt, the girls must climb up from the bottom of the idol industry by building their reputation and writing their own songs. Fortunately, Hemo Midori, an experienced idol and a big fan of Sakura, decides to join the group. With smiles on their faces, Sakura and the other girls work hard to become popular idols, ensuring that each day is as enjoyable as the previous one.