Chapters 3 through 12 of the light novel detail the protagonist, Nanjo Hiroya, a first-year high school student, becoming involved with Koga Yuzuki, a classmate who attends school via the infirmary.
The narrative begins with Hiroya visiting the school infirmary after injuring his leg during physical education. There, he encounters the school nurse, Shida Riko, an old friend of his mother, Minato Misato. Riko, a playful and teasing individual, introduces Hiroya to Yuzuki, who is also in the infirmary. Riko, noticing Yuzuki's struggles with academics, suggests that Hiroya, who is a good student, tutor her. Hiroya is initially hesitant and flustered by the suggestion and Yuzuki's presence, but after some gentle persuasion from Riko and a brief conversation with his mother, he agrees to consider it.
The following day, Hiroya nervously approaches the infirmary to give his answer. Riko, however, preempts him, informing him that Yuzuki has already been told he will tutor her. This unexpected turn of events leaves Hiroya flustered but committed. He then confides in his close friend, Kitayama Yasumasa, about the situation. Yasumasa, while surprised by Hiroya's newfound social interaction, offers his support.
Over the next few days, Hiroya begins tutoring Yuzuki in the infirmary. He discovers that Yuzuki, despite her pleasant demeanor, is academically challenged, particularly in math. Their tutoring sessions are often interrupted by Riko's teasing or Yuzuki's own struggles with the material. During this time, Hiroya also has a brief, awkward encounter with Watanabe Fuuka, a popular classmate, who bumps into him and later asks if he saw her drop a keychain, which he denies.
The chapters also touch upon Hiroya's home life, revealing a strained relationship between his parents. His father is often absent, and his mother exhibits a quiet sadness. Hiroya spends his weekends taking photographs, a hobby he enjoys, and plans to meet Yasumasa for lunch.
During a weekend lunch with Yasumasa at a fast-food restaurant, Hiroya is shocked to see Yuzuki there with her middle school friends, Miwa and Setsuna. Yasumasa also notices Yuzuki and her friends, commenting on their attractiveness, which causes Hiroya to accidentally spit out his drink. Yuzuki, witnessing this, is amused but promises not to tell anyone. The encounter leaves Hiroya flustered but also hints at a growing connection between him and Yuzuki. Yuzuki, in turn, reflects on her own insecurities and her desire to be genuine, while also admitting to her friends that she met someone from school.
The chapters conclude with Hiroya continuing his tutoring sessions with Yuzuki, navigating Riko's teasing, and dealing with his own developing feelings and social interactions, all while his home life remains a subtle undercurrent of concern.
