The story takes place in a post-apocalyptic Japan, where a mysterious catastrophe known as the "Great Disaster" has reshaped the world. The remnants of humanity have coalesced into a rural, isolated community called Kamiyama, where a rigid social hierarchy and strict rules govern everyday life. The protagonist, Satoru Mikami, and his friends begin to question the perfection of their world as they uncover dark secrets and anomalies.
