Tania and Gon have become accustomed to life in Fantasiburgo: the dragons' supermarket, the siren concerts and the TV shows of orcs. But their tranquility comes to an end with the arrival of Nene, a shy sphinx who is the new support teacher.

Why do adults disappear from school? Does it have something to do with the tiger that has escaped from the zoo? And above all: why the sphinx teacher never asks the students, if she is a teacher and she is a sphinx!?