"When you have your long hair tied as a ponytail, the happiness with come to you..." That is a secret between Yui and her mother from long ago, a secret that she only told to a mystery boy. Many years after that, she's still never met him, until when she is in grade 8. Her encounter with two strange boys, Fredy and Gunji, has revealed, not only the identity of that mystery boy, but also the truth about her family.