Two months after remarrying a man with a teenage son, Mirin begins noticing subtle changes in their relationship. One day, while practicing her favorite yoga routine, she is secretly watched by her stepson. In that moment, a new emotion stirs within him, and he decides to confess his feelings. Though Mirin outwardly acts as a kind and gentle wife, deep inside she harbors a deeply depraved and lustful nature. Driven by a strong desire to respond to his affection, she gives in to her urges and takes action. As their bond intensifies, her husband becomes aware of the situation and engages in adulterous acts involving both mother and son.