Alvaro Jameson was a normal freshman until a few weeks ago when he discovered that wizards and monsters were real. Following a strange young woman named Mariko Takashi, he uncovered a world hidden from people like him. As punishment for allowing a regular human to witness magic, Mariko lost most of her powers. She must work with Alvaro to solve crimes and protect the school, to prove that she can be responsible and regain her abilities. Now a dangerous changeling has come to their school, and no one knows who it's pretending to be. Can the two put aside their differences and find the creature before it's too late?