A growing empire connects the small pockets of remaining civilization.
Unknown technology is still in use and the air is filled with poisonous spores from the forest.
It's a story about the environment. During the Reconstruction period following the end of World War II, the U.S. occupied Japan. The infrastructure of Japanese government was in shambles and the air was filled with smoke from newly built factories struggling to catch up technologically with the rest of the world. Just like Grave of the Fireflies , it took the aspects of World War II and changed it into a heart - wrenching story about a peaceful people invaded by an evil empire. While the spores and smoke hurt many of the people, they were for the good of the country.