Toilet-bound Hanako-kun, Vol. 6

Through the workings of the School Mystery Clock Keepers, Kamome Academy's
entire student body is covered in wrinkles!? To restore peace to the school,
Hanako-kun teams up with a certain someone. Just when they thought the case was
headed to its conclusion, the secret of Hanako-kun's assistant Nene is brought
to light! What could it possibly be!?