In an ordinary history class, blood suddenly dripped down the blackboard, promulgating the first death rule:
[Keep quiet and no noise is allowed.
A classmate's sneer led to the ending of being swallowed up by the shadow and completely erased.
Lin Mo, an unknown student, was forced to become the "brain" for analyzing the rules. Trapped with him are the rational and cold-faced repeat student Su Tong, the passionate and impulsive sports student Lei Hao, the intuitive social expert Xia Youyou, and the history teacher with ulterior motives.
Escape from the classroom is not liberation, but stepping into a greater purgatory. On the campus shrouded in gray fog, every step may trigger new death rules: silent canteen, infinite corridors, living library...
However, they soon discovered that all this was far from a nightmare. The strange news push received by the mobile phone shows that their actions can have a weak impact on the real world and bring about "civilization echoes"!
From desperate survival to shouldering the heavy responsibility of civilization's survival, they must uncover the truth behind the school's anomalies - unjust cases decades ago, the forgotten "gatekeepers", a hungry existence called "the other side", and the covetousness of the radical faction "Ark" hidden deep within the official organization "Seventh Bureau"...
Under the rules is the testing ground of human nature. Can they survive mutual suspicion and deadly rules, find a way to purify the anomaly, and prevent the collapse of the real world? And where will their gradually awakening and costly "abilities" lead them?
This is a strange war on a familiar campus, a cruel adventure to survive and keep the world alive.
