Hakubo centers on the everyday life of Sachi Koyama, a high school violinist with promising talent. While Sachi is satisfied with her school life and maintains friendships within the music club, her preferred pastime is enjoying the scenery around her neighborhood in Iwaki, Fukushima, as she walks alone to her bus stop. However, during one of Sachi's after-school walks, she has an unexpected encounter with Yuusuke Kijinami, a boy she frequently notices on her bus ride home. After offering to help Kijinami find the perfect view of the evening landscape—the subject of his next painting for his art club's exhibition—the two form a bond over their shared appreciation of the beautiful scenery bathed in sunset. This chance meeting brings together these two souls who yearn to cherish the present, fully aware of how easily it can all slip away.