Lu Chen, a college student, accidentally discovered that the "Ivy League University" where he was studying would turn into a realm of rules and strange stories after midnight. All teachers and students staying on campus must abide by a constantly updated "Campus Safety Code", otherwise they will be "assimilated" into part of the campus. Lu Chen accidentally awakened his "rule vision" - he could see the hidden annotations, distortion marks and smeared original versions of the rules. In order to uncover the truth behind the rules and survive, he must use this ability to navigate the campus where weirdness spreads, and confront the gradually "abnormal" classmates, teachers and even campus buildings. Finally, he discovers that the university is actually a living cage imprisoning "unspeakable things", and he himself is the "spare key" of this cage.
