Hettie is in serious trouble. Cackle's Accademy operates a "three strikes and out" policy and Hettie has already had two warnings. If she gets another she will be expelled from the school forever. Her best friends, Cressie and Mona, try to help her but Hettie thinks she has found the perfect solution to her problem when Caspian asks her to deliver a bottle of obedience potion to Miss Swoop. Hettie takes a large gulp and tops the bottle up with ink. At first it seems to work and Hettie is a model of good behaviour. But Belladonna finds out what she has done and sets Hettie a terrible task, which she MUST obey... Belladonna and Cynthia find this out so use it to get Hettie expelled. Mona and Cressie work on a plan to get her reinstated.