Houkagogakari

When the midnight chime rings, we are captured in a "Houkago." In there, there is neither a correct answer nor a goal or a stage clear. Only our dead bodies are piled up.

One day, elementary school student Kei Nimori witnesses his name suddenly written on the blackboard in the classroom along with the mysterious word "Houkagogakari"... In the peculiar school called "Houkagogakari," where monsters are recorded and suppressed at the risk of their lives, the "midnight fairy tale" of boys and girls is now unlocked.

(Source: Kadokawa, translated)