Mildred's chances of passing the upcoming potion exam look slim; she is trying to study for it in the greenhouse with Mr. Blossom (even Blossom knows his potions better than her), while he feeds his plants tea leaves.
Meanwhile, Mr Blossom's chances of winning the local gardening competition are sabotaged by his rival, Terry Root. 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. Terry Root then sneaks out to the greenhouse, and has an altercation with Mr. Blossom about who's going to win the marrow growing contest.
Later on, Mildred and her friends are practicing for their test, but the only way she can remember the ingrediants is to sing them, but Miss Hardbroom tells them to be quiet and informs them that they can't practice any extra curricular magic. Ethel gets an idea and sneaks out to the greenhouse with Drusilla. She pours a sticky potion on the ground and they watch as the farmer comes back and drains one of Mr. Blossom's marrows. Unfrotunatly, his feet get stuck and he smashes everything in sight before running away.
Mildred and Maud come bounding out the front door of the academy to see what the noise is. They are quickly followed by Miss Hardbroom, who accuses them of causing the disruption. She tells them to go back inside, but Mildred's feet are cleaved to the ground. After freeing her, Miss Hardbroom follows the trail of slimy potion into the greenhouse and demands to see everyone who's been helping Mr. Blossom the next morning.
Mildred and Maud are assigned to clean up the greenhouse, and while they're at it they find one marrow untouched and decide a growing potion will help Mr Blossom win the competition. Ethel and Drusilla overhear and get another brilliant idea.
Miss Hardbroom informs the class that one student must go and help with the award presentation and natuarally chooses Ethel. Ethel passes the duty on to Mildred to the collective "What?"s of everyone involved.
While Miss Drill and Mildred are inside the tent housing the competition, Ethel and Drusilla sneak about and pump a growing potion into Mr. Blossom's marrow, which causes it to explode. Miss Hardbroom catches them before they can get away, and proceeds into the tent where a food fight had broken out between Mr. Blossom and Terry Root.
After they leave, Mildred apologises to Miss Hardbroom straight away about the trouble she caused (believing that it was her potion with caused the marrow to explode). Miss Hardbroom tells her about Ethel and Drusilla and suggests that she study for the exam.
Mildred gives herself a peptalk and prepares to write the exam. When she turns it over she sees that Miss Hardbroom (who has pointedly looked away) has chosen the make a plant growing potion for the exam.
Mildred: "Miss Hardbroom, we heard a noise and came down to investigate."
HB: "You made a noise you mean, and I came to investigate!"
Ethel: “I choose ... Mildred Hubble.”
- Miss Hardbroom might have changed the examination paper, it’s on making a plant growing potion which Mildred knows how to do.
- Other pupils are seen to find the potion memory song rather funny, and two can be seen tapping along a tune.
The Worst Witch TV Series