One day in the Yamaguchi family's bathroom, in a roll of toilet paper, appears a mysterious (and tiny) girl named Shin - for friends Shini - who at first glance makes a stunning impression on Nobuo, a simple middle school student.
"And if I used all the paper," thought Nobuo, and a drop of sweat rolled down his temple - "Would I see her then ... na ... naked ?!"
And so it begins, a wonderful story of love, lust and ... much more!

The main character Totoki is an ordinary high-school student who leads a mundane school life.
One day, a mysterious, primitive girl, Cherry appears before Totoki! Whatever Cherry does is a mammoth class! Because of that, Totoki is being thrown around mercilessly! Is Totoki's normal life gradually changing?!