 Mildred s potion exam, and a gardening competition for Mr. Blossom are both happening at the same time. Mildred s chances of passing look slim, as Ethel and Drusilla conspire to get her thrown out of Cackle s. Frank s chances of winning are sabotaged by his rival, Terry Root. Mr. Root has persuaded Miss Cackle (with a certain amount of blackmail concerning the girls  behaviour in the village) to allow the gardening competition to take place in the Academy Courtyard. Miss Hardbroom is absolutely opposed to the idea, especially since it might distract the girls from their exams. When Mr. Blossom s greenhouse is trashed and his marrows are destroyed, Miss Hardbroom who suspects Mildred and her friends, forbids the girls to have anything more to do with gardening - after they have cleared up the mess of course. Mildred and Maud find one marrow untouched and decide a growing potion will help Frank win the competition. Of course, Ethel and Drusilla see this as a chance to get Mildred in big trouble with H.B. The growing potion turns out to be the right answer for both Mildred and Frank, while Ethel s plans blow up in everybody s face.