While her husband is away on a work assignment, Sayaka, a mature woman and stepmother to Yoshi, lives alone with him. Gradually, she becomes aware of Yoshi as a man, her heart stirred by his warmth. Meanwhile, Yoshi is also drawn to his stepmother, fantasizing about taking her in front of his friends, overwhelmed by desire and jealousy. One night, he sneaks into Sayaka's bedroom and touches her body. Their suppressed feelings begin to intertwine, giving rise to a forbidden relationship.