The Niiyama family was once very happy until a major incident occurred, the three sisters suddenly passed away in an accident, leaving two mothers and children to take care of each other. Not long after, the mother Niiyama also passed away because she couldn't bear it, in the family there must be a man as a strong pillar for life to become easier. The period before the stepfather arrived, the two mothers and children were extremely lacking in affection, so Niiyama easily fell in love with the stepfather because of his caring and gentle actions. During a shared bath, she could not control herself and showed intense sexual desire in front of the stepfather, he also understood the girl's psychology so he did not hesitate to help relieve the psychological pressure of a young girl in her adolescence.