It's been 15 years since I married my husband. Reiko's only son, Tomonori, is blessed with good friends, and is living a happy life. One day, Reiko, who was driving a car, ends up in a collision accident. Fortunately, Reiko was not injured, but panicked, and left alone. I don't know that my son's classmates are watching this. When Reiko returns home, she regrets what she did earlier. Then the chimes in the house rang...