MJ, Jayden, Ella, and CJ are the children of the original Descendants. One night, the princess of Auradon gets a surprise visit from her grandmother, Maleficent, who still wants to have revenge on Auradon. She then steals her grand-daughter's prized possession, which is a ring that was gifted to her on the day she was born, and plans to use it to take over the land. So, the children, plus their friends Franny and Lory, must stop the villains before their precious world is gone forever.