Masahiro lives with his father after bereavement of his mother. - Masahiro is living a neat life because his father's skill is not enough to balance work and childcare. - At that time, Anna, whose father remarried and became her mother-in-law, arrives. - When she was shocked to see the rough house of her single-mother family, she started by cleaning Masahiro's room in an attempt to improve Masahiro's life. - However, Masahiro, who has entered her territory and raises her repulsion so much, plans to harass her in an attempt to push her away ...