If you try really hard playing tennis, you will be given angel wings," a boy told Yuuka when she was small. She still plays tennis, believing his words. She finally encounters the boy when she grows up.

To cheer up a sickly girl, Kuniya Ichiriki promised to one day "become energetic, become a name detective!" The words became real in the spring of his second year of high school. That beautiful girl, Utsunomiya...