A doctor who specializes in a particular kinds of mental illness was assigned to treat two girls who, due to the shock of an accident, had lost their memories and had stopped growing to protect themselves. The girls were traveling with their parents when they were involved in a car accident and saw their parents die in front of their eyes. But the girls say they don't remember the incident. This is probably the result of the body's...well, brain's self-defense to protect its own psyche. Moreover, they say they spend most of the day in “sleep,” partly because of the drugs they were given to stop the flashbacks.

It is also true that thanks to the shock of the accident and the effects, that the girls did not have their egos broken. As numerous cases have shown, girls with this condition often lose their ego with age. It was too late for that to happen, so they were brought here from a relative's house. However, the treatment that can be given is not always effective, and can only be given within a very limited time frame.

Another characteristic of this disease is that when they are released from the disease, they have proven to have a tremendous learning ability as they grow up. The doctor has been looking into the vocational aptitude of both of these girls and have decided to help them reintegrate into society, or rather, make a significant contribution to it.

They in front of the protagonist's home in a cab. We see them for the first time, the young sisters.

[From Getchu]