After construction crews destroy an old well, one of the members gets attacked in the port-a-potty.  Later, all of the toilets in Satsuki's school flood.  The students are informed that they will have to use the facilities in the old school if necessary.  Satsuki wants to stay away but must go when her little brother shows up needing to go to the bathroom.  While there she runs into Hajime and Momoko.  Hajime is attacked in the stall and it's up to Satsuki to use the Ghost Diary to trap the bathroom ghost before Hajime is pulled into the spirit realm.