Maud's Big Mistake is the eighth episode of The Worst Witch (2017 TV Series). It was first broadcast on CBBC and CBBC HD on 22 February 2017. It is preceded by The Best Teacher, and followed by The First Witch.
Mildred, Maud and Enid are brewing a potion when it blows up on them. Miss Hardbroom appears and reminds them that that night is parents' evening and she will be talking to their parents. Maud is worried that her parents won't be happy with the mistakes she's made. Maud talks to her parents through the magic mirror, and it is mentioned that Maud's mother was a student at Cackle's.
Enid offers to help Maud by giving her a forgetting powder, to make everyone forget her mistakes. When the parents arrive, Mildred finds her mother talking to the other parents about witchy things, and wonders if she's secretly a witch. Upstairs, Maud takes all the evidence of her mistakes and sprinkles the forgetting powder on them.
Maud and her parents go to see the teachers, and they all say that Maud is a perfect student, except for Miss Hardbroom, who can't remember what she was going to say. Maud goes to tell Mildred that the forgetting powder worked, but Mildred can't remember their friendship. Maud realises that her mistakes were mainly caused by Mildred, and that the forgetting powder has caused everyone to forget that she is friends with Mildred- even Mildred herself.
Mildred and her mother see Miss Hardbroom, who goes through Mildred's mishaps week by week, but Julie stands up for her daughter, pointing out that Mildred hasn't actually broken any rules in the witches' code and that as a senior witch, Miss Hardbroom has a duty of care towards junior witches like Mildred. Mildred wonders how her mother even knows the witches code.
Miss Cackle then appears and talks to Mildred and her mother, saying that Mildred doesn't really fit in because she hasn't made any friends that are a positive influence (they have all forgotten about Maud's friendship) and Mildred decides she wants to leave the Academy. Maud tells Enid what's happened, while Ethel discovers that her mother is using a projection spell to attend Ethel's parents' evening appointments because she can't be bothered to come, even though she plans to come for Esmerelda's prize giving the next week.
On the advice of Mr Nightshade, Maud and Enid go to the first aid cabinet and get a vial of remembering powder of which there is only one dose, but when they attempt to use it, Mildred runs in and messes it up. Mildred's mother follows her in and breathes in the powder. Mildred asks her if she remembers being a witch, but she explains that she's not a witch, but was just making small talk to fit in with the other parents, and she knew the witches' code because the school gave her a copy along with the other paperwork when Mildred was enrolled.
Mildred suggests that Maud needs to make a bigger mistake so everyone will remember about their friendship. When Maud gets up to give her speech as head of year, she tells everyone what she's done, then mixes the same potion that blew up the potion lab earlier. Miss Hardbroom sends Maud, Enid and Mildred to Miss Cackle's office, saying that they are 'always in it together'- their plan has worked and everyone remembers Maud's mistakes and that she and Mildred are friends.
In Miss Cackle's office, Miss Hardbroom says that all three should be expelled, and tells Mr Nightshade that his money won't help this time. Maud's father gets out a forgetting powder, and uses it to make everyone forget that night. Maud's parents tell her that they are proud of her for standing up in front of everyone and telling the truth, and they take a family photo.