Descendants novels (Melissa de la Cruz)

When they begin receiving threatening messages they believe are from their villainous parents, Mal, Evie, Carlos, and Jay know they must return to the Isle of the Lost to find out what is going on before the plot to destroy Auradon succeeds.

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.