There has always been a rumor in Linri No. 1 Middle School.
It is said that every year, five hundred people from a grade are randomly selected to go to an unknown place.
There are no rules and order in the real world, and you can even kill each other, plunder and rob each other at a certain time... However, you have to follow the unique rules of this place. All the rules are made by one person, and no one knows his specific origins.
"Rule X: You don't get out."
"Number of rules: 1"
Intention: None