The manga chronicles the days of Sumire, a lively 16 years old girl. However, Sumire is not a common girl: she is a life-sized marionette, controlled by an old man in black clothes. Sumire seems unaware of her puppet nature, although the rest of the cast are very aware that she is a marionette, but they become more or less accustomed to her weird nature.

Sumire is a 17 year old high school girl who wants nothing more than to make friends with her new classmates. She's so dissappointed that they all seem to hate her, calling her a pervert, a dirty old man, creepy, weirdo... alas, what is a poor lifesized puppet to do in this cruel world.

Soon however, she gets accepted by her class and starts to change the futures of her classmates with 'her' unbridled enthusiasm.