The narrative focuses on Hanagen Orika, a high school student who has resolved to avoid romantic feelings after a painful middle school experience. His resolve is immediately tested when he finds a love letter in his shoe locker. Initially suspecting a prank, he decides to discard it at a convenience store. However, he is interrupted by his classmate, Hiiragi Yuzuki, who seems to be chasing after the letter's sender, Katase Sayo. Yuzuki confronts Orika with intense anger, but ultimately lets him go and pursues Sayo. Orika remains bewildered, convinced it was a prank that went awry.
The following day, Orika observes his classmates discussing the incident, but to his surprise, no one seems to be talking about him or the letter. He notices Yuzuki glaring at him, reinforcing his belief that something is amiss. Throughout the day, Yuzuki's intense stares make him uncomfortable. After school, Yuzuki corners Orika and forces him to follow her to an empty classroom. There, they find Sayo, who is clearly embarrassed. Yuzuki reveals that the letter was indeed part of a prank, and she demands Orika apologize to Sayo for ruining it. Orika, though initially resistant, apologizes for "ruining the prank." Sayo, however, clarifies that the letter was not a prank, but a genuine confession. This revelation shocks both Orika and Yuzuki. Sayo then asks Orika to be her friend, which he initially refuses. Yuzuki intervenes, insisting he accept, and Orika reluctantly agrees, leading to Sayo excitedly exchanging LINE information with him.
A week later, Orika is still communicating with Sayo via LINE, albeit with infrequent replies from his end, a habit stemming from his past trauma. He receives an invitation from Sayo to go out on Sunday, which he politely declines. Predictably, Yuzuki confronts him again, accusing him of being free on Sunday and informing him that she has already told Sayo he will go. Despite Orika's protests, Yuzuki insists he accompany them, stating she will also be there. Orika questions Yuzuki's strong insistence on him befriending Sayo, but she claims it's simply because Sayo is a dear friend.
On Sunday, Orika meets Yuzuki and Sayo at the designated meeting spot. Yuzuki, dressed stylishly, comments on Orika's surprisingly normal appearance for a loner. Sayo, in contrast, is shy and easily embarrassed, especially when Orika compliments her outfit. Yuzuki receives a phone call and briefly leaves them. While Orika follows Sayo around a women's clothing store, a persistent saleswoman mistakes them for a couple on a date. Orika intervenes, explaining Sayo is uncomfortable with aggressive sales tactics, which the saleswoman apologizes for. Yuzuki returns, and they move on to lunch at a hidden gem of a restaurant recommended by Yuzuki. During lunch, Yuzuki playfully suggests Orika should pay for everyone, which he refuses, insisting on splitting the bill. Yuzuki receives another call and leaves again.
After Yuzuki's departure, Sayo expresses her discomfort with Orika's polite demeanor towards her, contrasting it with his more casual interactions with Yuzuki. She wishes he would speak to her more casually. Orika, finding it difficult to switch from polite speech, eventually agrees to speak to her more casually, which makes Sayo happy. Yuzuki returns, noticing their cheerful interaction. The three then continue their outing, browsing shops, with Yuzuki and Sayo making purchases while Orika remains largely a spectator.
