Daiki Nemoto shares a fifth-grade classroom and neighborhood with Tsubomi Tachibana. He counts classmates Futoshi Kuki and Yō Saegusa among his friends. Recognized for his polite and helpful nature, Daiki proves reliable and frequently steps in when other boys tease girls in class, displaying particular protectiveness towards Tsubomi. This supportive behavior manifests in calming her during stressful moments, like her worry over her pregnant mother, and giving her a toy duck that becomes a cherished keepsake attached to her bag.

Though initially popular with various girls, including older ones, Daiki gradually develops specific romantic feelings for Tsubomi. This shift crystallizes after he and Tsubomi secretly witness Yō Saegusa and Yae Yamabuki kissing, an event that sparks his emotional awareness. He grapples with typical adolescent confusion, his newfound emotions making ordinary interactions with Tsubomi increasingly awkward. Internal conflict arises from his uncertainty about expressing his feelings despite a strong desire to support her.

A pivotal moment occurs when he catches Tsubomi to prevent a fall during the incident where they observe their friends kissing, heightening the mutual tension between them. Ultimately, Daiki reciprocates Tsubomi's confessed feelings, leading them to become a couple, marking his journey through first love and emotional maturation.