The family who moved into the new apartment is mother Keiko (You) with four children: Ming (Yumiya Yagira), Kyoko, Shigeru, and Snow. But the mother had to lie to the people around her that her husband went overseas to work and she lived with her eldest son. The truth is that the other three siblings are "black children" because the four children have different fathers. They have been staying at home and not going to school. When the mother went to work at the department store, the young Ming took over the responsibilities of the parent at home on behalf of her mother. Suddenly one day the mother disappeared, leaving the only 200,000 yen in cash and a short note in her hand to the children, and after entrusting the younger siblings to Ming's care, she quietly ran away from home. It is not easy for the four children who have no relatives and know almost nothing about the outside world to start facing a new life...