Some high school students discover that underneath their school there could be some tunnels that served as a bomb shelter during the war. Nobody remembers their existence, so they decide to try and find them. The students discover that some children were buried there when part of the tunnels collapsed and one of the girls, Aixa, begins to sense an inexplicable threat. According to some articles she finds on the Internet, the people buried there “appear” in the places where they died, so she considers it an “Evil School Omen”. “E.S.O.” Aixa tries to warn her friends but nobody believes her.