More than 150 years ago, a plague almost destroyed all civilizations on the surface with a very high fatality rate. The humans who managed to escape hid in special cave-shaped shelters, continuing the fire of human civilization. However, more than 150 years later, some people are questioning whether the plague of that year has completely disappeared 150 years later. Therefore, the fire of rebellion quietly arises, and will eventually lead to a huge whirlpool disaster that no one can escape.
