In the summer of 1945, this pair of brother and sister leaves a story that makes the world people shed tears. When the firefly is dead, the couple of brother and sister are sad for it. But when the brother and sister die, who will shed tears for them? At the end of World War II, the flames of war arrive in Japan. A pair of brother and sister who lose their parents and come across cold reception of their relatives are forced to hide in a deserted hole and suffer from hunger and cold. His greatest wish is to support his sister and chase the beautiful little fluorescent light with her. But his sister dies because of long-term malnutrition. On the night of September 21st, he also dies quietly like falling asleep. At the moment, the fluorescent lights are flickering.