Toilet-bound Hanako-kun, Vol. 1

This manga follows Nene Yashiro, an occult-loving high school girl who investigates the Seven Mysteries of Kamome Academy, including the legend of Hanako-san, who occupies the third stall of the third floor girls' bathroom. But when Nene summons Hanako-san, she finds out that he's not what she expected - he's a boy!