This is a young adult book, as all the characters are in high school, senior year. It's an interesting take on Disney villain origin stories, and posits the creation of faerie villains like Maleficent and Ursula is the result of non-fae attempting to bottle and sell fae magic. The experiment goes horribly, terribly wrong, of course, and the villains are victims of non-magical greed.
The story starts with the villains in high school in the Scar of Monarch City -- a place where fae magic used to rule, but literally disappeared and left behind a big, ugly vacuum called the Scar. All that's left behind are echoes of its brilliance, like perfect weather all the time and a magical garden. And a nasty, deadly black ink-water lake, called Miracle Lake, that kills all that falls into it. No one has magic any longer, but some experience traces of it. Families of magical fae are called Legacy. They're born with a distinctive, heart-shaped mark. It's very much a dystopian setting.
Ursula is the most recognizable villain, and she's the main character's best friend. The main character, Mary Elizabeth Heart, I understood to be the young Queen of Hearts, from Alice in Wonderland of "Off with her head!" fame, although that's truly left up for interpretation. Ursula's already a skilled blackmailer and has enemies in high school and out. Mary is dating James, aka Captain Hook from Peter Pan, and they're that couple, the one joined at the hip.
Mary's doing an unpaid internship for the local police department, and gets pulled into a Scar investigation when Mally, aka Maleficent, goes missing. Her super-rich father is convinced something bad has happened to her, especially when her raven is left behind.
Mary teams up with junior detective Bella, aka Beauty and the Beast's Belle. Soon Ursula disappears, too. Mary steps through the mirror in a local night club / hang out popular with Legacy kids, and not only is she nastier looking in her reflection, it takes her to a place where she figures out someone may be experimenting on Legacy!
Mary escapes, and she and Bella go through all the contacts on Ursula's phone, looking for clues, and phew! Things are getting nasty in the Scar, with non-Legacy encroaching, buying up property cheap, and Ursula's been a big supporter of Legacy by blackmailing non-Legacy council members to stay in line.
Then there are sightings of a monster by Miracle Lake, which is patently impossible, until a tentacle reaches out and transforms into... Ursula. She spills the beans. I won't spoil what happens, but it was an interesting take on how the villains were formed -- in response to cruelties by us non-magical folks.
This is an interesting new take on Disney villains and will make for an interesting read under the tree for Disney fans. Enjoy!