High school freshman Reo values a quiet, ordinary life, but her plans are upended when she reunites with Shion, a childhood friend who is now a senior at her new school. Shion's attention is anything but casual: his gaze is unnervingly intense, and his calculating yet natural-seeming closeness leaves Reo constantly on edge. She declares that she hates him and wants nothing to do with him, but Shion's possessiveness only deepens, and Reo slowly realizes that resistance is futile. What begins as a one-sided, suffocating pursuit gradually shifts as Reo finds herself drawn into a relationship she cannot escape. The manga follows their push-and-pull dynamic as Reo grudgingly accepts Shion's obsessive love and begins to develop feelings of her own, navigating a high school life with no exit route. The story is set entirely within a Japanese high school environment, centering on the senpai–kōhai relationship and the intensity of a childhood connection rekindled under unexpected circumstances. Notable narrative arcs include the initial confrontation where Reo feels trapped, the transition into a reluctant but increasingly genuine romance after she takes the offensive by agreeing to date him, and the subsequent deepening of Shion's devotion as Reo's own emotions grow. The series also includes a short bonus story titled "Kouhai-kun no Aishikata."