Advanced placement into a school of higher grade proof-reading is determined by the results of the Promotion Test strictly for class type. Ranging from A class with the best facilities anyone can offer all the way down to F Class which is composed of low dining tables, rotten tatami mats and other worn out facilities. Students can change classes by competing using the Examination Summons Battle system or ESB. Students summon characters with their equivalent test mark scores and use them to compete with other classes.
While sorting through a mess of books in the staff room, Ohana happens upon one of Denroku's log books from long ago. Within it, it recounts a story of Ohana's mom when she was the same age as her.
Mahiro Yasaka is just an ordinary high school student, until one day he is suddenly attacked by a dangerous monster. Just when everything seems to be lost, he is saved by a strange girl named Nyaruko, who claims to be the shape-shifting deity Nyarlathotep from horror author H. P. Lovecraft's Cthulhu Mythos.
