Suguru returns home to find his sister-in-law Moe in a state of desperate arousal, expressing her neglected passions. Her bold advances strip away his hesitation, and they give in to a forbidden, fiery union. Their shared lust erupts into intense, unrestrained sex, deepening their illicit bond and relinquishing all pretense of innocence, solidifying a secret affair built on raw physical need and mutual transgression.