Chapters 3-12 of the light novel introduce the protagonist, Iguchi Keita, a high school student who prefers solitary commutes by train, immersing himself in books. His routine is disrupted when a junior student, Yoneyama Maharu, returns his lost earbud tip. Maharu, also a student at Keita's school, reveals she uses the same less-popular train line and expresses a desire to "interact more" with him, finding their shared commute a valuable opportunity. Keita, initially resistant and valuing his quiet travel time, is drawn into Maharu's persistent attempts to engage him.
Maharu's primary motivation is to overcome her own boredom and connect with people, particularly Keita, whom she finds intriguing due to his reserved nature and love for reading. She cleverly uses Keita's own stated preference for discovering the unknown to justify her persistent questioning. Keita, on the other hand, desires a peaceful commute for reading and introspection, viewing Maharu's advances as an intrusion. However, he is also intrigued by her directness and the challenge she presents.
Their interactions quickly evolve into a daily ritual. Maharu establishes a "contract" where they each ask one question per day, requiring an honest answer. This leads to Keita revealing he is the student council president and a member of the library committee, much to Maharu's surprise given his perceived lack of social skills. Maharu, in turn, reveals she is in the art club. The dynamic shifts as Keita starts to anticipate their daily exchanges, even strategizing to avoid Maharu, only to be outmaneuvered.
A significant turning point occurs when Maharu requests Keita's LINE account. Keita initially resists, fearing it will further encroach on his personal time. However, he cleverly uses his "one question" privilege to counter, showing Maharu his phone's battery usage statistics, which reveal he uses Twitter more than LINE. This forces Maharu to accept his LINE account, but she quickly adapts, and they exchange contact information.
The narrative progresses to their daily train commutes, where Maharu continues to probe Keita with questions, often related to his preferences and activities. Keita, while still valuing his quiet time, begins to engage more, even admitting to enjoying their conversations and finding them "interesting." He also reveals a past involvement in tennis, surprising Maharu. The chapters culminate in Maharu asking Keita on a "date," defining it as simply meeting to get to know each other better, a definition Keita, despite his initial hesitation and surprise, accepts, agreeing to meet her on Saturday afternoon. This marks a significant shift in their relationship, moving from reluctant daily encounters to a planned outing.