Newly hired art teacher Mitsuro Kawase, 23, expects an uneventful start at a high school, but his routine is upended when the popular and charismatic senior teacher Toshiaki Kazama abruptly confesses his love. Kawase initially dismisses it as a joke, but Kazama's persistent, bold advances soon make it impossible to ignore. As Kawase is gradually drawn into an intense romance, he struggles with his own hesitation and the fear of social judgment. The relationship is further complicated by the jealousy of Kawase's younger brother, Hitoshi, who harbors possessive feelings. The story follows the push-and-pull between the reserved, bewildered Kawase and the confident, unwavering Kazama as they navigate their secret workplace affair, eventually moving from the school's after-hours hallways and empty staff rooms toward a deeper commitment. The narrative arc traces Kawase's emotional journey from confusion and shame to acceptance and mutual desire, with key tension arising from his internal conflict and external obstacles such as family interference.