The anime takes place in Tokyo in 2030. In a suburban area, suddenly a high-frequency resonant sound is heard, and at the same time a red mist shrouds the area. Anyone who hears the sound, be it human or animal, loses consciousness. The government estimates that it might be an unidentified virus, and fearful of an epidemic, blockades Tokyo and moves its base to Osaka. However, six days after the incident, those who lost consciousness from the sound awaken for no apparent reason. Those blockaded in Tokyo slowly start to get the city functioning again, but after that day strange incidents start to occur at the blockade border. Those who have awakened a hidden blood power arise, are drawn to one another, and must face a cruel fate.
— Description from AniList community (anilist.co).
