Chapters 3-12 of the light novel introduce the central characters, Kazami Issatsu and Kamishiro Airi, who are childhood friends and neighbors, often mistaken for a couple due to their close proximity and shared activities. Airi, a strikingly beautiful girl with golden hair and blue eyes, is described as "fairy-like" and is admired by many male students. Issatsu is a slightly taller, quiet boy who has known Airi since birth. Their parents are close friends, and they have always been together, attending the same schools and spending much of their time in each other's company.
The narrative begins with a scene set in a classroom at dusk, where Airi playfully suggests they try kissing. This leads to a flashback to an early morning, detailing the daily routine of students arriving at school. Airi's arrival causes a stir, with students commenting on her beauty and some expressing romantic interest. However, their attention quickly shifts to Issatsu, who is walking beside her. The students refer to them as a "baka couple" (idiotic couple) and "married couple," much to Airi's annoyance, as she insists they are just childhood friends.
Their close relationship is further explored as they argue about their daily commutes and the perceived obligation from their parents to look after each other. This argument escalates into a typical "lovers' quarrel" that draws the attention of classmates. Despite their frequent bickering, their bond is deep, and they quickly reconcile, acknowledging that their relationship is unique and unaffected by external perceptions. They discuss how their closeness, which stems from a lack of romantic awareness and a familial comfort, is misinterpreted by others.
A turning point occurs when, after a heated argument about their perceived lack of romantic feelings for each other, Airi impulsively suggests they try kissing. Issatsu, initially taken aback, accepts the challenge, spurred by his competitive nature and a desire to prove Airi wrong. Their first kiss is awkward and filled with nervous anticipation. Both characters experience physical reactions, such as blushing and increased heartbeats, which they try to dismiss as mere nervousness due to their first experience. They agree that kissing is not something to be done lightly, and they decide to avoid such actions in the future, attributing their reactions to the novelty of the experience rather than romantic feelings.
Later, Airi reflects on the kiss, feeling a mix of guilt, transgression, and excitement, which she tries to rationalize as a fleeting sensation. Her mother's casual question about whether she has kissed Issatsu prompts a flustered denial, but her mother warns her about other girls potentially taking an interest in Issatsu, who has grown into a handsome and intelligent young man. Airi, despite her outward denial of feelings, shows signs of possessiveness and jealousy when her parents discuss Issatsu's potential romantic interests.
The narrative then shifts to a scene where Issatsu corners Airi in her room and confesses his feelings, asking to kiss her. This is followed by a flashback to a cold day at school where Airi, seeking to warm up, initiates a prolonged hug with Issatsu in a secluded corner of the classroom, further blurring the lines of their relationship. Issatsu, despite his initial discomfort and attempts to remain composed, is clearly affected by her actions.
Another significant event involves a prank by Airi, who hides Issatsu's eraser and leads him to the rooftop, only to playfully tease him by placing it in her bra. Issatsu, initially frustrated, eventually retrieves the eraser by complimenting her beauty, a genuine statement that visibly flusters Airi. He then warns her against such actions, which she interprets as him not wanting her to do such things with anyone else.
The chapters culminate in a dramatic scene on the rooftop where Airi, after a series of escalating provocations and a playful "confession" that turns out to be a prank, is genuinely flustered by Issatsu's direct questioning about her feelings. Issatsu, realizing the depth of her emotions, confesses his own growing feelings, stating that he has been thinking about her since their first kiss. Airi, overwhelmed, finally admits her love for him. The story ends with them sharing a kiss, marking a significant turning point in their relationship from childhood friends to something more.
