Former members of the Sakura Junior High tennis club gather for a New Year's Eve reunion and a ski trip, where old feelings resurface between the group's former idol, Mizuho, and Tatsuya. Struggling with her fragile health, Mizuho attempts to leave town to find independence and strength on her own. However, Tatsuya pursues her, leading to a passionate confession of love and a promise to stay together despite the distances between them.
During a class reunion, the playful yet tense relationship between childhood friends Tatsuya and Ayu takes center stage. A flashback to a New Year's celebration reveals a romantic rivalry involving Ayu's cousin, Mamoru, which forces the two dense friends to confront their true feelings. After Mamoru gracefully steps aside, Ayu confesses a long-held childhood promise, and she and Tatsuya finally admit their love for one another.