This summary covers chapters 3 through 12 of the light novel, detailing the initial events and character introductions.
The protagonist, Aiba Rin, is a quiet, introverted high school student who prefers to avoid social interaction. His solitary life is disrupted during his commute home when he encounters a beautiful, unnamed classmate being harassed by a group of older male students in a park. Despite his desire to remain uninvolved, the students block the path, forcing Rin to intervene. He uses his smartphone to record the situation and then confronts the harassers, demanding to pass. The girl recognizes him as "Aiba-kun," revealing his name and his attendance number being first alphabetically. The situation escalates when one of the male students grabs Rin by the collar. Rin, though physically unprepared for a fight, calmly but firmly threatens to involve the police, highlighting the legal ramifications of their actions. His logical and unyielding stance causes the other students to back down, leaving the main aggressor isolated. Under pressure, the student reluctantly apologizes. Rin then records the group, warning them against future retaliation and stating the video is for his protection. He leaves, concerned about being late for his part-time job.
The next morning at school, the girl, revealed to be Konoha Takane, approaches Rin to thank him. She mentions calling the police after he left, but they found no one. Their conversation is brief and awkward, as they have little in common. Rin reflects on his past experiences with social interactions, particularly a childhood incident where he was falsely accused of being in a relationship with a classmate, leading to her public distress and his decision to avoid initiating conversations with others. He maintains a detached, solitary existence, finding comfort in his routine and independence.
After Golden Week, Rin notices posters for a lost white cat named Mao. On his way home, he revisits the park where he encountered Takane. He spots Mao near the public restrooms and, recognizing the cat from the posters, calls out to it. Mao, being a housecat, readily approaches Rin. While holding Mao, Rin calls the number on the poster. Takane arrives, relieved to find her cat. She expresses gratitude to Rin for finding Mao, and they walk together towards the park exit. Takane reveals she was hesitant to use that exit after the previous incident. During their walk, Rin explains his part-time job at a Yamame trout farm, detailing the tasks involved. Takane expresses concern about his work schedule and the fact that he is working despite school rules, hinting at his difficult financial situation due to his parents' recent death.
Rin's parents died two months prior in a tragic traffic accident caused by a drunk and drowsy truck driver. As an only child, he was left to live alone. A family meeting decided he would live with his maternal grandparents, who were eager to care for their only grandson. However, attending his desired public high school from their home was impossible due to the distance. After exploring options, it was arranged for him to attend Shiramine Academy, a private school, on a scholarship due to his academic achievements, including passing the entrance exam for a prestigious public high school. This arrangement requires him to maintain excellent grades to retain his scholarship.
At school, Rin's academic success becomes apparent. During the first midterm exams, he scores a perfect 100 in mathematics, surprising his classmates and the teacher. He learns he is the only student to achieve this perfect score, placing him first in the grade. This achievement draws unwanted attention, which he finds uncomfortable. He also learns that the class representative, Sasamoto Takahiro, who was the top scorer on the entrance exam, placed second. Rin's academic performance solidifies his position as a valuable student for the school's academic department, which they are trying to strengthen alongside their renowned sports program. His interactions with Takane and her friends, including Sasamoto and Tsuruse Ayumi, are starting to become more frequent, though Rin remains reserved and socially awkward.
