Mildred and her friends try to join Ethel's Cauldron Club, but Mildred fails the initiation test after interference from Ethel. Luckily for Mildred, Fenella & Griselda, come to the rescue and create the Dangerous Old Books Society! Soon the stuffy old club begins to lose its luster & it's members! Meanwhile Miss Drill contemplates quitting after growing tired of Miss Hardbroom's harassment.

Mildred, Maud, Ethel & Drusilla are sent on work experience to Mrs Cosie's Cafe & learn all there is about running a restaurant. That is until Ethel changes the Cafe to be the way she likes it. Ethel claims its just for fun, but when a group of tourists & Grand Wizard Hellibore all arrive at the same time the girls must find a way to get out of the mess!

Ruby's study of the theory of relativity results in several of the girls hoping to unlock the secrets of the past, by traveling back in time! Due to Ethel's tampering, their little experiment goes haywire and brings two ancient waring witches into the 21st century! Now the very fate of the castle relies on, Mildred!

Cackle's Academy takes part in a quiz show against girls from the dreaded Pentangle's School. Mildred is angry to find that Miss Cackle allows Ethel to be on the team, but not her! Additionally Miss Hardbroom refuses to have anything to do with it, but in the soon changes her mind, as the reputation of the school & personal pride against the snooty Pentangle students is on the line!

Miss Cackle's young niece, Gabrielle Gribble, comes to the Academy for teaching practice. Suffering from a bit of stage fright, Gabrielle takes Miss. Hardbroom's advice of being tough a little to0 seriously & she becomes a tyrant who throws the entire class in detention within minutes of her first day. Soon Mildred & her friends end up teaching her far more than she ever learned in College.

It's time for the dreaded Third Year Witch Project where nerves are frayed & unlikely partnerships forged! The girl's projects range from the typical of a retrieval spell, to the unique of a mini broom to the downright odd of chewing gum that never loses its flavor! The final demonstration in the Great Hall nearly ends in disaster, but all the girls work together to make the day memorable.

Miss Hecketty Broomhead returns to Cackle's Academy to take over while Miss Cackle goes to look after her sick aunt. She takes an instant dislike to Mildred & even forces her to wear a tracking bracelet at all times! Meanwhile her insistence on rigid time-keeping proves to be quite the problem, especially when she is considered to be a permanent replacement for Miss Cackle!

Mildred discovers that there is something which she is not worst at - drawing. Ethel, however, who can't bear the thought of anybody being better than her at anything, is determined to thwart Mildred. Part of Ethel's scheme involves her "client' Drusilla winning a prestigous art contest judged by the new art teacher at Cackle's.

Mildred & the other girls notice Miss Drill is down in the dumps. They decide to give her a potion which will allow the non-magical Miss Drill to temporarily gain magical powers! Now the other teachers are trying to help Miss Drill hone her powers, while the suspicious Ethel & Drusilla try to prove that Mildred & her friends are behind it all!

The girls of Cackle's Academy make a good will trip to the all boy's Camelot College. Unfortunately the boys they're visiting are not exactly rolling out the red carpet for Mildred & the others! Even worse is there is rumor of a merger between the two schools, but Mildred and her friends devise a plan which is guaranteed to make Miss Cackle change her mind.

Love is in the air, or at least Miss Crotchet thinks it is. The visiting Professor Von Raffenberg seems to be smitten with her, but it turns out he is a conman, who is looking for the Lost Chord, which will grant the owner perfect luck! Some of the girls can see right through him, while others are conned into helping him.

As their third year grows to a close the girls sneak out to attend a local Fair. When Miss Cackle discovers them, she hears Mildred mocking her, the usually kind Miss Cackle punishes the whole school! Feeling this is unfair Mildred & Jadu decide to create a newspaper that mocks the teachers & has a list of their demands for how the school should be ran! Once discovered the two face expulsion!

Mildred & Jadu's expulsions are on the horizon & the other girls try to find a way to save them. The girls plan on running Maude for Head girl hoping to use their influence to save the two. When that plan falls through they decide steal Ms. Cackle's spell book & they end up creating a danger far greater than they've ever faced! Now it's up to Mildred to save the day!