The First Witch is the ninth episode of The Worst Witch (2017 TV Series). It was first broadcast on CBBC and CBBC HD on 1 March 2017. It is preceded by Maud's Big Mistake, and followed by Spelling Bee.
Ethel has a wart, which is apparently the mark of a powerful witch, so everyone else wants one too. Mildred didn't know this, and it makes her feel bad about being from a non witch family. Maud suggests Mildred look in the book 'A Brief Witchery of the World', suggesting that maybe Mildred has witch ancestors. She also lets Mildred use her styling brush.
Mildred gets the brush caught in her hair, and can't get it out. She turns up late for Mr Rowan-Webb's class, wearing her hat to cover it. After class, Maud and Enid are wondering if there's a spell that could fix it, when Ethel suggests a simpler way, and cuts the brush off with scissors- including the chunk of hair that is tangled around it. Miss Hardbroom then appears and sends them to Miss Cackle's office.
In potions class, Mildred, Maud and Enid are making a growing potion to use on Mildred's hair, when what looks like a flock of bats streams in. They are actually invitations to join the first year coven, a witching tradition, but you have to solve a riddle to get in. Maud then applies the potion to Mildred's hair, but nothing happens.
While everyone else tries to solve the clue, Mildred talks to Miss Bat about whether she might have witch ancestors, and Miss Bat suggests they look in the school records to see if any other Hubbles have attended the school. They go down to the dungeons, where the records are kept, and Miss Bat uses a spell to search the files, but Mildred is the only Hubble in the records. While in the dungeons, they encounter a flock of bats nesting there, and Mildred gets bat drool in her hair.
Mildred meets up with Maud and Enid, who have decided to take the clue literally, and search 'high and low' in the school for the answer. Mildred says she didn't see anything in the dungeons, so they head up to the roof. Mean while, Ethel is sending other students in the wrong direction, to ensure she gets to the coven first.
Mildred, Maud and Enid encounter Ethel and Drusilla heading up to the roof too, meanwhile Mildred's hair has started to grow; the potion must have a delayed effect. Mildred then trips over, her hair has grown all the way to the floor, and isn't stopping! Mildred, Maud, Enid, Ethel and Drusilla all end up tangled in the rapidly growing hair. Outside, Miss Cackle and Miss Hardbroom see the hair growing out the window, and hurry to the scene. The hair is growing out into the stairwell, and Miss Hardbroom identifies it as Mildred's.
The others ask Ethel to fix it because she's the powerful witch with the wart, but she can't get the hair to stop growing, and admits that her wart isn't real; she faked it to get attention. Without knowing exactly what went wrong with the potion, they can't fix it. Mildred then mentions being drooled on by the bats, and it turns out that bat drool is an amplifier- it makes spells and potions stronger.
Outside, Miss Hardbroom is about to stop the hair, but Miss Cackle tells her to wait and see how the girls handle it, despite the hair now tangling around the two teachers as well. Mildred gets them all to chant together, which finally stops the hair growing, and causes a gateway to open. Mildred enters, followed by the others. Inside, the teachers are waiting to induct them into the coven. Mildred still thinks she isn't a witch, as none of her family are, but Maud points out that that makes Mildred the first witch in her family, which is just as impressive. They are all inducted into the coven, and as Mildred entered first, she is the founder of the coven and gets to name it, so she calls it the 'Hairy Sisters'.