A self-shot masturbation video lands on the phone of Araki Tomoya, a casual and flirtatious high school student. The sender is Shiina Ao, a serious and studious classmate who openly dislikes Araki. Believing the video was a mistake, Shiina demands Araki delete it immediately, but Araki finds Shiina's frantic reaction intriguing. Teasing him, Araki pins Shiina down and brings him to climax, discovering that Shiina, despite his prim exterior, is not entirely opposed to sexual acts. Araki proposes they become sex friends, but Shiina refuses. The reason for the refusal becomes clear: the video was never intended for Araki. Shiina had filmed it for someone else—a person he has a secret, unrequited crush on. The story follows the tense, shifting dynamic between the two classmates as Araki's persistent interest clashes with Shiina's conflicted heart, creating a love triangle rooted in hidden feelings, forced proximity, and the messy boundary between physical convenience and genuine emotion.