In Xinhai City, an unknown energy pulse (codenamed "Abyss Echo") originating from deep-sea ruins swept across the world, and a handful of humans awakened a variety of strange powers. However, this gift comes with a secret shackles - when the awakened person uses his abilities, he will irreversibly accelerate the growth of his own "life entropy", eventually leading to physical collapse or mental distortion, known in history as the "Abyss of Sin".
