What is it... that you are seeing?
A distorted, faint voice constantly haunts Aki, becoming his companion. He has no idea why. The train station, his mother's dead body, and a white transparent being in his nightmare...
As soon as the siren sound starts, it makes Aki see something he doesn't recognize. This siren wave is something else. A warning? Or a reminder?
Reiji, a non-human being, falls for him. After these two meet, the hidden world falls into chaos. The betrayer who can seamlessly dwell in these two different worlds and rule over them emerges as a threat to the non-humans.
