More than fifty years ago, due to the rampant discharge of nuclear sewage by an island country, the radiation of marine life mutated.
The mutated marine creatures were mentally confused, rioted and attacked, and coastal cities were severely destroyed.
A global effort was made to clean up mutant organisms. The use of nuclear weapons caused the space of the pollution source to expand, creating a stable dimensional rift. Behind the dimensional rift was an unknown continent. From then on, the door to a new world opened.
