Cassy and Gus sit in a magic chair made by Merlin and Cassy starts to change into a tree and Gus starts to turn into a werewolf! They have to find all the ingredients for the spell. But Zarlak is trying to get at least one of the ingredients first! And we find out a big secret about Verne! What could it be?
A giant girl named Ilsa comes to Vonderland and becomes roommates with Cassy. Cassy keeps trying to help her fit in, but Lucretia (one of the evil twins) keeps doing spells behind her back to make it seem like Cassy is making fun of her. Lucretia pretends to be her friend and gets Ilsa kidnapped by Zarlak! The trio have to save her!
Cassy and Gus make fun of Verne for being a mortie. He gets mad and leaves. He goes to the mortie arcade. He has a magical artifact in his backpack. It turns Verne into a powerful dark wizard. Later it Cassy into a powerful dark sorceress. It's up to Gus to stop them from destroying the earth and each other!
Zarlak has captured small beings called ""the tricky trolls"", but one escaped and come to the kids. Zarlak then send his dragon to steal their magic book, but took Verne (who turned into into UBOS) instead, then they kidnap Gus, leaving Cassy to save the day, who is having a hard time using her shape-changing powers. Will she be able to save the day by turning into Zarlak?
A mortie(non-magic person) named Verne comes to a magic school. He meets Gus, a half-elf second year junior wizard and Cassy, a third year junior witch. He also meets the evil twins: Lucretia and Borgia. He also meets the headmistress Miss Crystalgazer. He also meets a prince that has been enchanted to look like a toy frog. He also meets Ubos, a book that can talk and take them to the center of the earth where an evil wizard Zarlak is stealing magic from the outside world. He becomes good friends with Cassy and Gus! Three Is a Charm, after all!