The story follows Kiyama Shuuya, a self-proclaimed "introverted" high school student who, despite his preference for a quiet life, desires a girlfriend. He attends a prestigious high school where he maintains a decent academic standing through last-minute cramming, though he struggles with pop quizzes. His only close friend is Haruyama Akira, a popular and outgoing "sunny" type who is exceptionally handsome.
The narrative begins with Shuuya's typical morning routine, where he skillfully avoids social interactions. Akira approaches him, and they discuss Shuuya's academic talent and his desire for a girlfriend. Their conversation is interrupted by the arrival of Tachibana Koyomi, the school's most beautiful girl, who is constantly pursued by admirers but rejects all advances. Akira playfully suggests Shuuya pursue Koyomi, which Shuuya dismisses due to her popularity and past rejections, stating he wants to experience love's transformative power rather than just seeking a partner.
During lunch, Shuuya eats with Akira, who is curious about Shuuya's independent living situation and his ability to make bento boxes. Shuuya explains his desire for self-sufficiency, inspired by classical literature. Their conversation is interrupted by Mogami Kaito, a friend of Akira's, who seeks romantic advice. Kaito wants to make his crush like him before confessing. Shuuya, despite his initial reluctance, advises Kaito to increase his "appeal" by demonstrating benefits like academic achievement, suggesting Kaito focus on upcoming exams. Kaito leaves, inspired by Shuuya's advice.
Later, as Shuuya and Akira head back to class, they overhear Koyomi and her friends, the "Divine Seven," discussing a "punishment game" where the loser has to confess. To Shuuya's shock, the punishment is revealed to be a confession to him. Shuuya, believing this is a prank to humiliate him, defiantly declares he will reject Koyomi, anticipating the backlash from her friends, particularly the formidable Manamoto Daichi. However, Koyomi, surprisingly, accepts the "punishment" and agrees to date Shuuya.
The next day, Shuuya and Koyomi meet for their "fake" relationship, with Shuuya intending to maintain a distant facade. During their first outing, they are interrupted by Sakai Sho, a charismatic older man who claims to be Koyomi's childhood friend and ex-boyfriend. Sho proceeds to recount embarrassing stories about Koyomi's past, including her childhood crush on him and a period where she drastically changed her personality to win him over. Shuuya, initially annoyed by the interruption and Sho's self-centered storytelling, becomes increasingly frustrated. He defends Koyomi, pointing out that changing for someone you love is natural and that Sho's behavior is more questionable than Koyomi's past. Shuuya's passionate defense, fueled by his own desire to protect Koyomi and his annoyance at Sho's insensitivity, leads to Sho's departure.
Koyomi, deeply affected by Shuuya's defense and his acceptance of her past, confesses her genuine feelings for him. Shuuya, though initially intending to keep their relationship purely transactional, finds himself touched by her sincerity. Their budding relationship is further complicated by the watchful eyes of the Divine Seven and the lingering presence of Sho, who seems intent on disrupting their newfound connection. The narrative hints at the complexities of their relationship, with Shuuya struggling to reconcile his desire for a girlfriend with his introverted nature and Koyomi battling her past insecurities.