Hinnoissa saattaa olla eroa myyntipisteen mukaan.
It started off innocently enough: Hui-min had intended to quickly sneak in and out to hide some chocolates in the locker of a classmate. But as soon as he stepped foot inside the shutters slammed closed for the night, locking him inside with possessed janitors hellbent on killing intruders, and vengeful ghosts eager to sap his lifeforce away.
Can Hui-min sneak though the school and discover a way out? Or is he fated to become yet another ghost haunting the classrooms of Yeondoo High School?