Enormous conch-shelled gastropods have surfaced in droves all over Japan. Despite Professor Yajima's protests, the government is propelled by the ambition of a certain figure towards the forceful extermination of the creatures. As a result, the world is gripped by fearsome circumstance!

Japanese businesses struggle after steep goals for greenhouse gas emission reduction are set. However, something rises to their aid. Monsters called "Prana" evidently have the ability to purify air. People blindly put their faith in the Prana, but their size grows.