On the verge of her thirties, Sayaka lives happily with her hardworking husband. One afternoon, as she indulges in solo pleasure, gently soothing her own body, a construction worker suddenly catches sight of her sweaty form and forcefully takes her. Shocked by the man's intense presence, she finds herself repeatedly drawn to his powerful physique, overwhelmed by pleasures she's never known before. The way this stranger touches her, his body heat, the sound of his breathing—everything shakes Sayaka to her core. Torn between guilt over betraying her husband and the uncontrollable ecstasy surging through her, Sayaka trembles passionately in the throes of desire.