Toilet-Bound Hanako-kun is a supernatural school story built on an actual Japanese urban legend - Hanako-san, the ghost of a girl in the third stall of the girls' bathroom. The series makes the ghost a boy, keeps the bathroom, and builds seven school mysteries around it.
The art direction is the immediate draw. It's designed like a picture book, with muted vintage colours, patterned backgrounds and framing that borrows from Taishō-era illustration. Very little in anime looks like this.
Nene Yashiro makes a good protagonist because her motivations are small and human - she wants a boyfriend, she's insecure about her ankles - while she's negotiating with entities that can rewrite reality.
The series gets considerably darker as it goes. Hanako's cheerful deflection is a cover for what he actually is and what he actually did, and the reveal reframes the earlier comedy uncomfortably.
This collection covers Hanako, Nene and the school's mysteries.