Arcana has two famous families of science: the precise and methodical Flasks and their sneaky neighbors the von Offels who have stolen credit for every scientific breakthrough the Flasks have ever made. And it's about to happen again. Ethan Flask is a popular sixth-grade science teacher. The mysterious, ghostly Professor von Offel is supposed to be reviewing him for a prestigious teaching award. What he really wants is for Flask to unwittingly help him become fully corporeal again.