The story revolves around a supernatural phenomenon called "Reverberation". Outbursts of certain extreme emotions, especially fear and pain, leave "imprints" or "echoes" in space and time, like recordings. These "reverberations" can not only be perceived by sensitive people, but can even distort reality, replaying and superimposing horrific scenes from the past in the present, and attracting nameless things that feed on these emotions. The protagonist and his party are forced into a huge maze of horror intertwined by countless "reverberations". They must find the source of the "reverberations" and close it before their own sanity is swallowed up, otherwise the entire city and even the world will become an eternal nightmare corridor.
