Haunted School by Hideyuki Hirayama

6.10

A young girl wanders into a wing of her elementary school that has been abandoned for years and is rumored to be haunted. When she doesn't come back, a group of her classmates go looking for her, only to find that they, too, are trapped inside. They must somehow find their way to safety, and quickly, because the rumors of ghosts are turning out to be true.