Corpseparty: Musume

It happened after school one rainy day... A group of friends have stayed behind to prepare for the next day’s school festival. One moment they are idly telling ghost stories but the next an enormous earthquake strikes and the entire school seems to fall down around them. They awake to find themselves trapped in a parallel version of their school. As school abandoned and disheveled and whose calendar dates back to 1927. Can they find a way out of this nightmare or are they doomed to the same fate that befell the other victims whose corpses that lie numerous throughout the school? Note: Chapter counts contains an extra chapter and an origin chapter.