The narrative begins with the protagonist, Naru, experiencing the devastating pain of a breakup. His girlfriend of three years, Aika, confesses she has found someone else and can no longer be with him. Despite Naru's disbelief and pleas, Aika tearfully ends their relationship, leaving him heartbroken and questioning the nature of love. He feels overwhelmed by sadness, crying uncontrollably in public, and resolves to never want love again.
A few days later, during his commute to high school, Naru encounters a girl whose skirt is blown up by the wind, revealing her underwear. He accidentally blurts out "Pink," leading to him being slapped by the embarrassed girl, whom he finds attractive despite the painful encounter. He confides in his friend Yukki about the incident, who dismisses it as a lucky break. Yukki also notices Naru is still hung up on Aika, urging him to move on. Naru admits he's struggling to forget her, especially since they are in the same class at their new high school, a situation he finds unbearable and a constant source of melancholy. He feels a pervasive sense of unease, loss of appetite, irritability, and sleeplessness, leading to feelings of bitterness and a desire to disappear. He reflects on how his past positive experiences with love have now been replaced by the negative impact of heartbreak, realizing the inadequacy of platitudes he may have offered to friends in similar situations.
Seeking solace, Naru retreats to his room and finds himself captivated by a female singer-songwriter on social media. Her clear yet powerful voice, accompanied by an acoustic guitar, deeply resonates with him, offering a sense of healing. This inspires him to pick up his own guitar, an instrument he once dreamed of mastering but had let become a burden. He decides to aim for a future collaboration with the singer, seeing a parallel between his own "heartbreak" and the guitar he had previously neglected.
The next day, Naru heads to school with his guitar, intending to join the light music club. He meets Yukki, who is pleased to see him finally engaging with high school life. After school, Naru visits the club room and begins playing the singer's song, arranging it to complement her voice. He is interrupted by the arrival of the "pink girl" from the "panty incident." To his surprise, she is the singer he admires. She introduces herself as Iori Kubota and, after a brief, awkward exchange where Naru mistakenly thanks her for the slap, she recognizes him as the "peeping pervert." Despite his initial misstep, Naru expresses his admiration for her music and his desire to join the club. Iori, impressed by his rendition of her original song, invites him to play with her. Their first session is electrifying, creating a powerful synergy that overwhelms Naru and makes him feel alive again.
Their performance is overheard by another student, Yui Kawase, who is impressed and welcomes Naru into the club. Iori, visibly flustered by Naru's talent and their connection, impulsively asks him to be her exclusive guitarist. Naru, having just set a goal to play with her, readily accepts. Yui notes that Iori, the school's unofficial idol, seems smitten with Naru, a suggestion Iori vehemently denies before fleeing the room. Naru, though still processing his lingering feelings for Aika, feels he has taken a significant step forward.
Yui explains the club's structure and reveals that both she and Iori are second-year students. She praises Naru's guitar skills, suggesting they are beyond a high school level. Naru admits he once aspired to be a professional but felt his dream was broken. He expresses his excitement about playing with Iori, and Yui hints at the challenges of being involved with Iori, who has a fan club.
The next morning, Iori waits for Naru at the site of their first encounter. Despite his initial hesitation to call her by her first name, he eventually does, solidifying their new dynamic as exclusive collaborators. They struggle to find conversation topics, but as they approach the school gate, they both try to speak about their recent jam session. Naru's use of Iori's name draws envious stares from other boys, highlighting her idol status.
