Shin'ya, who lost his mother at a young age, and Yuuka, who feels out of place at home, establish the "Free Time Club" at school by chance. The two, feeling lonely, gradually grow closer. However, Yuuka suddenly disappears, leaving Shin'ya with nowhere to go, and he waits alone for Yuuka to return, keeping the promise they made. Thirty years later, Yuuka's secret is finally revealed.