Daishin Nakano has just moved from Fukuoka to Tokyo to start university at O University. Overwhelmed by stylish classmates who speak perfect standard Japanese, he feels out of place. He recalls being comforted six months earlier, when mourning his pet cockatiel, by an upperclassman—Takara Shiga.

On orders from club president Minami Uebashi, Takara accompanies Daishin to the hospital after he’s injured during a trial camp. Though blunt, Takara’s subtle kindness touches Daishin, who becomes eager to thank him with a gift.

Daishin is delighted when he gives Takara a glass marble and they grow closer. He joins the mountain climbing club and starts to enjoy life in Tokyo, making friends with classmates like Emiri Shinomiya. But something still weighs on his heart…

After Takara casually says, "Some guys like guys," Daishin becomes confused. Is what he feels for Takara admiration or something deeper? Emiri introduces him to “oshi-katsu” (fangirling/fan activities), which helps him reflect on his feelings.

As summer break begins, Daishin realizes he won’t see Takara for a while and feels down. He spends time with Emiri, Mei Hyodo, and Kenzo Yukawa until he gets invited to the club's fireworks event.

During a hiking meeting, Takara receives a call that excites members Aki Ishikawa and Yui Ogawa, who suspect it's from a girl. Daishin becomes increasingly curious—and jealous—about who keeps calling Takara.

After running a fever, Daishin wakes up in Takara’s room, embarrassed about nearly confessing the night before. Takara confronts him: “Do you like me?” Confused, Daishin is unsure how to respond—until Takara kisses him.

Now dating his crush, Daishin begins to worry he’s not good enough for Takara. To reassure him, Takara suggests going out together. Daishin plans their first date—birdwatching—as a heartfelt gesture.

Takara talks with his best friend Aki about the future. As Daishin becomes a bigger part of his life, Takara wonders if he should stay with him. Wanting to be honest, he invites Daishin on a hike to share his thoughts.

Daishin returns to Fukuoka, worried about his mother Tomiko. Thankfully, her condition isn’t serious. He calls Takara that night to update him, and soothed by his voice, falls asleep at peace.