A world where modern cities and "mythical asylums" intersect. Hidden in human civilization are mythical creatures called "echoes of the past" (such as gods and demons in Eastern and Western myths). They awaken due to fluctuations in human beliefs and cause disasters. The global secret organization "Lawful Alliance" established a "special asylum" to imprison out-of-control "echoes" and "deviants" who have awakened superpowers.
