Night Has Come Season 1 Episode 1

When class 2-3 arrives at a retreat center, the rest of the classes are nowhere to be found. Their homeroom teacher goes out to look for the missing classes, and they are left alone in the building. Meanwhile, Yoon-seo and all of her classmates get a message out of the blue. With the rules of the game, each one of them receives a role, and the game begins.