Misaki Takaoka is a blue-haired, cyan-eyed high school student who nurtures a secret affection for her step-brother Makoto, rooted in childhood. Her unspoken emotions simmer beneath the surface, escalating until she surreptitiously seeks solace in his bed—a risky act discovered by Makoto, unraveling her concealed longing. The revelation forces both to confront their suppressed attraction, culminating in a clandestine physical relationship that transitions from hidden yearnings to shared understanding.

Her tsundere nature manifests as an outwardly aloof, sharp-tongued facade concealing guarded tenderness. The story centers on her struggle to reconcile societal taboos with her forbidden desires, framing her conflicted dynamic with Makoto as a tense clash between duty and passion.