Toilet-bound Hanako-kun, Vol. 8

It's been three days since they returned from within School Mystery Three,
the Hell of Mirrors. To cheer up the depressed Kou, Nene heads to the
Boundaries' Tanabata festival. She was supposed to be enjoying the festival with
Hanako-kun and Kou, but suddenly she finds herself fifty years in the past-and
happens to meet the living Hanako-kun there!?