Descendants novels (Melissa de la Cruz)

Mal, Evie, Carlos, and Jay have received threatening messages demanding they return home. They have a sneaking suspicion that their villainous parents are behind the messages, and something Evie sees in her Magic Mirror confirms their fears. Although Maleficent's just a tiny lizard after her confrontation with Mal, could she have found a way to escape? Mal and her friends determine to sneak back to the Isle to get to the bottom of the mystery.

Mal, Evie, Jay and Carlos make a plan to use their upcoming visit to the Isle of the Lost to help other villain kids attend Auradon Prep, while Uma teams up with Hades to bring down the barrier and get her revenge on Mal.