Raised in an orphanage, mother Ayano had always dreamed of family warmth due to being abandoned by her parents. However, caught between her husband Keiji and their son Takayuki, both chasing their own dreams, the family began to fracture, leaving Ayano emotionally tormented. Before marriage, Ayano had been introduced to anal pleasure by a special man from the orphanage, and ever since, she sought that same sensation in every sexual encounter with her husband. This hidden desire deeply affected her son Takayuki, and one day, their mother-son relationship took a shocking, incestuous turn.