Eniale and Dewiel are an angel and demon, respectively, who are often at odds with each other on borrowing one another’s makeup without asking, or gathering souls for their employers. In one of their apocalyptic fights, they find a baby and search for its mother using means that send humanity into a panic. After destroying their clothes in another fight, the two travel to Paris to replenish their wardrobe, and an exorcist discerns and chases after Dewi relentlessly. A little girl summons both the angel and demon to help her sick mother recover, and it’s a competition to see who can win the little girl over to “their side.” After Eni pisses her friend off completely, Dewi “helps” Eni build the “perfect” hot springs and vows to drain Eni’s seemingly endless supply of money.

Nene Yashiro and Kou Minamoto are trying to find out more about Hanako-kun. A mysterious student tells Nene to look inside the 4pm Book Stack - a secret part of the library only accessible after 4pm. Inside of it are legions of books about the students of the school. White books are about current, living students; black books are about dead students; and you must not read the red books. Nene and Kou find the hidden entrance and search the black books for Hanako’s book, but they can’t find anything. Then, Nene finds her own book, and the pages and book turn red while she’s reading it, prompting Mystery Number Five, Tsuchigomori-Sensei, to attack her!

Nene Yashiro, Hanako-kun, and the exorcist Minamoto have ventured into the Misaki Stairs, one of the school’s seven mysteries, to rescue Yashiro’s friend Aoi.  Inside is a creepy staircase with piles of books and other bits the spirit has collected over the years. The three are given a terrible task of putting together a body out of scrap pieces for the spirit, who is trying to recreate a teacher from her past. Later, Minamoto’s older brother, also an exorcist, wants to exorcise Hanako, claiming that it’s only a matter of time before Hanako turns evil and tries to kill a student.

Despite its ridiculous title, this was a really fun book. Hanako-kun is one of the seven mysteries of Yashiro’s school. She summons Hanako-kun one day because she’s heard she can be granted one wish, but Hanako is nothing like she expected. To begin with, he’s a boy bound to a toilet in the girls' bathroom! Yashiro is desperate to be part of a couple, so she eats a mermaid scale and tries to give its matching scale to a boy she has a crush on (as legend says he will be inexplicably bound to her forever), but she chickens out at the last minute. The scale turns her into a fish, but Hanako eats the matching scale to save her from a worse fate, and fights off the mermaid who has come to claim Yashiro. From that point on, Hanako and Yashiro and bound together with a supernatural bond. Yashiro becomes Hanako’s assistant and the two continue to explore the supernatural elements of the school, keeping them from harming the mortal students whenever possible.

Alex continues her search for her sister, and only a select few people can remember her.  She gets help from a few other students who decide to recreate the gate spell, but this will be painstaking and take a lot of effort.  Meanwhile, Teacher ferrets out the one who betrayed the hunters, and he moves his group into a safe house with Mr. Roi, the eccentric teacher who has also been giving extra lessons to Alex.  We also learn about Nereshai, an ancient race of extremely powerful magic users, and the Sohrem, a group of powerful magical beings who have begun searching for new hosts within the school building.  Centuries ago, the Nereshai sealed the Sohrem, but that seal has been broken, and it's up to the students and teachers to put everything right and bring home those who have been forgotten.