Description
When Mitsuhiko and Rio, his old friend, are at school, a loud explosion happens.... They go to the roof of the school building and find Koiboshi, their classmate, standing vacantly.... Just when Koiboshi falls down, her body is suddenly surrounded by a strange light and Mitsuhiko loses his consciousness.... A while later, he wakes up and sees an unbelievable scene. As a matter of fact, his school subsided deep into the ground because of an earthquake.... With his friends and teachers, they try to find a way to get out....