His father is a simple, strong, and earnest man, but his new wife, Satsuki, is a woman of great sex appeal and beauty, a mismatch for his honest father... His son, Koichi, feels uneasy about their relationship. Then one day, his premonition turns out to be true. While his father is away, Satsuki has been meeting with a young man on a regular basis. Koichi feels intense anger at Satsuki's betrayal of his family, but when he sees her for the first time, his lust is aroused. He forces her into a forbidden physical relationship, on the condition that he not tell his father about it.