The father's new wife, beautiful and around the same age as his son, had become an object of his desire. Determined that this couldn't continue, the son decides to leave home. Their last outing as a family is a trip to a hot spring resort. The father falls asleep drunk, leaving the son alone with his stunning stepmother. Unable to contain himself, the son succumbs to his urges and seeks his mother's affection. Though confused, she's unable to resist his passion and accepts a single night of love. Lost in the thrill of forbidden incest and the potent young cock, both stepmother and son drown in pleasure, their story a tale of illicit intimacy.