Esmerelda Hallow, Ethel's older sister, gives the students a tour and Miss Cackle helps Mildred cope with the effects of a transfer spell.
Mildred attempts to make friends with Maud by, but she unknowingly reveals hers and Enid's plan to get Muddles out of Miss Cackle's study over their maglets.
Mildred performs her magic display, a beaker and bottle band, but she messes up when the potions explode over the staff and The Great Wizard insists Miss Cackle leaves.
The pupils call home and Ethel is hurt when her mum can't spare the time to speak to her, after spending ages talking to Esmerelda.
Suddenly, the old Mrs Cackle enters the scene and helps Mildred to make herself a non-naughty witch and fixing the past by not expelling Mona.
With the castle crumbling down, Mildred starts chanting and brings all the girls into a circle and casts an incredibly powerful spell that reverses all of Agatha's evil magic and turns everyone back to themselves again.
The Great Wizard traps Agatha and Miss Gullet into a photograph of them both, which Ada hangs up in her office for the rest of time.
Mildred and Ethel become joined together by the arm, which Miss Cackle reveals is a friendship trap that will only undo when they make friends and Sybil refuses to leave her room after recent events.
Beatrice's asthma transports her and Sybil to different places around the school whilst the friendship trap begins to wear off between Mildred and Ethel when they talk about Esmerelda having no magical powers.
Miss Pentangle arrives at Cackles Academy to run some modern magic workshops, with students speculating she is the new headmistress.
Miss Pentangle impresses the first years with her modern chanting and gives Mildred a power boost in order to perform an invisibility spell in potions.
Ethel decides to sacrifice her magic to the stone, but she is too late as when she makes a speech, Miss Hardbroom, Esmerelda and Sybil are put into ice blocks, and then she is.
As the festivities unfold, Miss Cackle gives a brief, but emotional, speech to the rest of the school that while there's stuff needed to be cleaned up, they will celebrate that they are not just students and staff anymore, that they're a family.
After Mildred uses the stolen Wishing Star to give her mother magic, Julie has no idea how to control her amazing new powers.
With half the school including Ethel, Miss Cackle, Maud and Enid gone, Julie's magic spins out of control and Mildred learns from Miss Hardbroom that she wished her non-magical friend (Indigo Moon) magical too and she got addicted and it ended with her being turned by stone into a statue so its all up to Mildred to make sure the same won't occur to her Mum.
Eventually, Mildred's potion restores the cat and Miss Drill agrees not to punish the girls for their mistake, but she will for throwing a secret party!
When Indigo disappears after being humiliated by Miss Hardbroom again on her first day at Cackles, Mildred and Maud track her to a TV talent show in a nearby city and wangle their way into the studio.
Final appearances: Philip Martin Brown as Mr. Rowan-Webb and Wendy Craig as Miss Bat When an apparently botched potions experiment leaves Mildred with a whole new look, can she complete three impossible challenges and reverse the spell before the sun goes down?
Meanwhile, Beatrice, Sybil and Clarice have become part of the junior coven and are tasked by leader Fenella to prove their loyalty by teaching first year Izzy Jones (Peppercorn in the end credits) how to ride a broom.
First appearances: Saoirse Addison as Izzy Jones and Billie Boullet as Fenella Feverfew It is Indigo's birthday celebrations, and she suddenly starts ageing 30 years for a few moments at time.
First appearance: Luciana Akpobaro as Azura Moon Clumsy Mr. Daisy, the new Spell Science teacher arrives at Cackles upsetting Mabel's sweet stall.
Mildred is conned into visiting the "fortune telling" Crystal Lake by an evil old crone, Jessica Juniper, masquerading as a girl from Pentangles in the magic mirror.
After a bit of digging it is found that Mildred needs her family's grounding stone to restore her magic, and since she has no idea where it is, Izzy's dad hatch's a plan to use the comet to create a new one.
Meanwhile, Maud analyses playback and realises someone else caused Miss Cackle's demise and deliberately gets herself sent to Wormwood too with a plan to free Mildred.
It turns out that Ethel was doing Agatha (Ada's evil twin) Cackle's bidding and tricked Felicity into sabotaging Mildred's spell.
Izzy and Azura discover Felicity's role in the plan, who eventually decides to confess to Miss Hardbroom but Ethel stops her by lying that she will do it.
In a sub-plot, an attempt to comfort (the soon to be dismissed) Mr Daisy with a Happiness Potion goes wrong, when he dances in an overly familiar way with an unimpressed Miss Hardbroom!
In the series finale, Agatha Cackle, impersonating headmistress Ada, promotes Ethel to head girl, and at the school assembly tricks everyone else into the Vanishment plane of existence, including Julie (who had been messaged by Maud).
She also demands the Great Wizard hands over his title or she will not reveal the secret word (the name of her first familiar) that will release the girls, Miss Drill and Julie from Vanishment.
When they reach the assembly hall, Mildred learns that Izzy Jones is her sister and Spike is her dad, who Julie met in Morocco just before she was born.