Chapters 3-12 of the light novel introduce the protagonist, Fujieda Kazuki, a university student majoring in composition at Teito Music University. He is presented as a somewhat withdrawn individual, seemingly more comfortable with classical music and his studies than social interaction. His personality is revealed through his interactions with his junior, Kagari Sena, a lively and energetic student who often clings to him. Kazuki is shown to be a dedicated student, though he struggles with a current composition assignment, being the only one in his seminar who hasn't submitted a piece.
A significant plot point is revealed when Kazuki admits to Sena that he is a fan of the popular idol group "TRUE MIRAGE," particularly their center, Tojo Mizuki. Mizuki is described as a "cool beauty" idol with exceptional talent in both singing and dancing, and a perfect appearance. Kazuki's admiration for her stems from her evident hard work and improvement, hinting at a deeper connection. This connection is confirmed when it's revealed that Mizuki is Kazuki's childhood friend, and he is surprised by her sudden rise to national fame.
The narrative then shifts to Kazuki's daily life. Sena, facing the risk of failing her courses and being held back a year, seeks Kazuki's help with her studies in exchange for cooking for him. They live in a rundown apartment building called "Mi casa," which is nearing demolition. During their grocery shopping, they encounter a suspicious woman in a hat and sunglasses, who reacts strangely to seeing Kazuki and Sena together, mistaking Sena for Kazuki's girlfriend. This woman is later revealed to be Mizuki, who has moved into the apartment next door.
Mizuki's behavior is erratic; she exhibits a childlike demeanor, contrasting sharply with her public idol persona. She expresses a desire to be Kazuki's neighbor again, revealing that she was allowed to live alone after years of being in dorms. Their shared past is explored, with Mizuki recalling Kazuki encouraging her to pursue her idol dreams. She interprets his past words in a highly romanticized way, believing that becoming the number one idol will allow her to live with him. This revelation about her motivations and deep-seated feelings for Kazuki is a significant turning point.
The story then delves into Kazuki's academic life. He participates in a practical exam where he performs Chopin's "Farewell Waltz," a piece he changed at the last minute. Sena is surprised by this, as he had been practicing a different piece. Kazuki explains he felt like playing it, and his performance is described as technically perfect but lacking emotional depth, earning him praise for his skill but also a comment about his "monster-like" ability to adapt.
Following Kazuki's performance, the focus shifts to his rival, Oosera Mao, a highly talented and ambitious pianist who is preparing for her own exam. Mao is portrayed as a strong competitor, and she insists Kazuki attend her performance, pulling him into the auditorium. Kazuki observes Mao's performance of Liszt's "Mazeppa," noting her "winning music" style, driven by a desire to win and be recognized. He contrasts this with his own past experiences of being forced to play for his parents' expectations.
Kazuki reflects on his own musical motivations, recalling how he used to play to make his childhood friend, Mizuki, happy. He realizes that his music was once driven by the joy of seeing her dance and sing along. This memory, triggered by Mizuki's recent visit and his conversation with Sena about different musical motivations, makes him want to see Mizuki again. The chapters conclude with Kazuki contemplating his past and his current feelings about music and his relationships.
