Miss Hardbroom's class have been gathering potion ingredients, but Belladonna has deliberately defied her teacher and brought in a highly dangerous plant. She uses its fruit to prepare a potion, uncertain what it's effect will be. Miss Cackle announces that the school is going to have an impromptu 'Offwitch Inspection' and orders them all to prepare for the Inspector's visit. As a reward for hard work, she invites everyone to share a glass of Witches' Brew, unaware that Belladonna's evil potion has ended up in the brew. Everyone who tastes the drink falls fast asleep and Hettie and her friends are left to save the school from closure with Miss Swoop's help.