When 14-year-old activist Veronica Vanderhall is suspended from school, her parents send her to Miss Genevieve's School for Difficult Girls, which claims to have an impeccable record for rehabilitating complicated girls with a "streak." Miss Genevieve and her students appear to be the picture of perfection, with impeccable manners and identical, immovable hairdos. However, Veronica soon discovers that those impeccable manners mask a dark secret, and hatches a plan to help the girls regain their voices.

As the only witch at her high school, Fiona has learned that the safest way to navigate her teen years is to blend in. She's over the moon that her secret crush, Emilio, has asked her to the homecoming dance. Then, her parents drop a bomb. Cousin Luna — who Fiona loves but considers "fresh off the broomstick" — is arriving from England and attending Fiona's school. Unlike Fiona, Luna is proud of being a witch and eager to show off her magical abilities. Fiona must decide if she'll continue to hide … or let them see the witch.