E.S.O. Entitat sobrenatural oculta (2009)

Some students find out that there could be some tunnels under their High School that were used as an anti-aircraft shelter during war. Lots of kids were left buried there and they decide to find them. One of the girls, Axia, starts to feel a threat, because it is said that the people buried in the tunnels haunt the places where they died. Finally, she tries to warn her colleagues against the danger, but no one believes her.