On the surface, high school student Koyuki "Koyun" Hikawa seems unapproachable and terrifying to most other students. In reality, Koyun is just insecure and prone to overthinking due to her uncomfortable experiences in middle school. However, her chance encounter with two boys in school—Minato Amamiya and Youta Hino—sparks a change in her. Like her friend Miki Azumi, the boys are never afraid to approach Koyun and see her for who she really is.

Although Koyun starts spending more time with Miki, Minato, and Youta, she finds herself torn between her newfound bliss and her fear of getting too attached to others. Meanwhile, each of her friends quietly struggles with their own challenges. But as the new friend group continues to navigate high school together, Koyun and the others start to break out of their shells and enjoy their adolescence to the fullest.