This semester at Bloor's Academy brings a few changes. There is a new art teacher, Mr. Boldova, and a new student, Belle, who lives with the Yewbeam aunts and seems to have a strange power over them.

Emma and Charlie soon discover Mr. Boldova's secret identity: He is the older brother of Ollie Sparks, the boy who lives in the attic of Bloor's Academy. Ollie had always been prying into matters that didn't concern him, so Ezekiel Bloor made him invisible. When Charlie and his friends find him, Ollie is alone and hungry. They promise to make Ollie visible again with the aid of his brother, Mr. Boldova.

Can Charlie and his friends save Ollie?