In Closed School, Yoo-ra suffers from nightmares every night. One day she meets her high school friends. Jin-tae is a promising artist, In-seok is a chaebol and former thug, Hye-jin likes In-seok, and Seong-ho, who used to be In-seok’s errand boy, finally meet up.
Yoo-ra asks her friends if they remember the classmate that killed herself. Everyone is flustered and claims they don’t.
Yoo-ra goes to the bathroom, but passes out after seeing herself in the mirror. Everyone gets in In-seok’s car to send Yoo-ra home, but they get into an accident and all become unconscious.
When they wake up, they are at a familiar school that’s closed. It was the school they went to that has closed down.
Why did they end up there? Yoo-ra and her friends tremble in fear for their lives…