In present-day Auradon, Ben, the benevolent teenage son of King Adam and Queen Belle, offers a chance of redemption for the troublemaking offspring of Disney's classic villains, Cruella De Vil, Maleficent, the Evil Queen and Jafar.

After Ben's coronation in Descendants, the villain kids Mal, Evie, Carlos and Jay settle in at being good while their villainous parents are still roaming the Isle of the Lost. The story goes deeper at the arrival of new villain kids, Freddie (Dr. Facilier's daughter), CJ (Captain Hook's daughter) and Zevon (Yzma's son).

When the pressure to be royally perfect gets to be too much for Mal, she returns to the Isle of the Lost. She discovers that Uma, the daughter of Ursula, has taken over as queen, and that her gang is finalizing plans to bring down the barrier.

Mal emerges from the shadows of a mystical forest onto a dark coastline where she crosses paths with Dizzy.

When a barrier breach jeopardises the safety of Auradon during their departure off the Isle, Mal resolves to permanently close the barrier, fearing that nemeses Uma and Hades will wreak vengeance on the kingdom. Despite her decision, an unfathomable dark force threatens the people of Auradon, and it's up to Mal and the VKs to save everyone in their most epic battle yet.