The Grand Wizard visits the academy to give a lecture, and he's accompanied by three trainee wizards, one of whom, ""Loppy Luggs"", could be described as the Worst Wizard.... The trainee wizards decide to make their visit into a boys vs girls affair.... During the lecture they cast a spell which makes some of the girls raise their hands but then become unable to speak. Mildred ends up firing a rubber from a ruler, which hits the Grand Wizard's head! She is then sent to her room.... The teachers organize a debate between the wizards and witches to find out who is better. The wizards get Loppy to make a potion which will give them an unfair advantage.... Mildred finds that she's left her potion book in the potion lab and so goes there to get it. There she finds Loppy, who is really called Merlin.... She finds out from him what the wizards are up to. The potion they made helps them to speak more confidently! She takes some of the potion and enters the hall where the debate is t