The two sisters were abandoned in an orphanage. They were each adopted by different families and gained different lives.
One day my younger sister came to join my elder sister and stayed at her house temporarily.
My sister had a nightmare one day and was woken up. The nightmare was that she had died in an accident.
At first I thought it was a nightmare, but then I realized that the same day had happened over and over again, and I realized that I was reborn.
Who is causing the accident? How many times will she have to be reborn to solve the mystery?
Purpose: Don't show mercy, live your life well