Three years ago, Hikaru lost her husband to illness and has since been supporting herself working as a sales clerk. One day, she received a call informing her that her father-in-law, Yasuo, had fallen ill, so she went to his house to take care of him. However, Yasuo had completely lost his memory, even forgetting Hikaru's existence, and was now severely senile. Hikaru found herself burdened with the dual responsibilities of her demanding job and caring for her incapacitated father-in-law, marking the beginning of an increasingly difficult life.