Cinderella and the Prince are having a picnic to celebrate their one-year anniversary. Meanwhile, at the Tremaine mansion, Cinderella’s stepsisters Anastasia and Drizella are bitterly doing Cinderella’s old chores. Anastasia wanders off to avoid work and stumbles upon the picnic. When the Fairy Godmother drops her wand, Anastasia takes it to her mother and sister. In the ensuing struggle, Anastasia inadvertently turns the Fairy Godmother into a garden gnome.
Lady Tremaine, reveling at yet another chance to ruin Cinderella’s life, uses the wand to go back in time to the day the Grand Duke fitted the glass slipper on Cinderella. She uses the wand to expand the slipper so that it can fit Anastasia, and the Grand Duke declares she must be the girl the Prince is looking for. Cinderella arrives on the scene too late, and Lady Tremaine destroys Cinderella’s other slipper – the only clue to her identity that she was the one who danced with the Prince. Cinderella decides to follow Lady Tremaine and her stepsisters to the palace with Jaq and Gus.
At first the Prince claims Anastasia was not the girl he danced with at the ball, but Lady Tremaine uses the wand to alter his memory, and he accepts her as his bride. Jaq and Gus witness this and inform Cinderella that Lady Tremaine has the Fairy Godmother’s wand. Cinderella poses as a maid to get into the Tremaines’ room, but she is spotted by Lady Tremaine and captured by the palace guards as an intruder. Cinderella briefly touches the Prince’s hand and he begins to recognize her, but Lady Tremaine orders Cinderella placed on the next ship out of the kingdom. The mice find the Prince and explain the whole story to him, and he rides off to intercept the ship just as it leaves port. The Prince embraces Cinderella and his true memories return. He asks her to marry him, and she accepts.
The Prince brings Cinderella back to the palace and explains everything to the King and the Grand Duke. The King orders the Tremaines arrested, but they escape using the wand. As Cinderella prepares for her wedding, Lady Tremaine emerges with Anastasia, who has been magically transformed into a doppelganger of Cinderella. Lady Tremaine then transports Cinderella, Jaq and Gus into the castle grounds, where they are to be taken to their deaths in a twisted pumpkin carriage with Lucifer as its human driver, but they manage to defeat Lucifer and escape, leaving Lucifer stranded in the woods.
Cinderella races to the castle as the vows are about to be exchanged. At the last moment, Anastasia’s conscience gets the better of her and she turns the Prince down. Lady Tremaine and Drizella reveal themselves in their fury. The King orders the Tremaines arrested, but Lady Tremaine uses the wand to fend off the guards. During the scuffle the wand’s magic is deflected, and Lady Tremaine and Drizella are turned into toads and transported to the castle cellar. Retrieving the wand, Anastasia reverts herself to her original form, and Cinderella restores the Fairy Godmother. The Fairy Godmother offers to reverse the timeline to its original state, but Cinderella and the Prince decline. The pair and married and live happily ever after again.
In a post-credits scene, Lady Tremaine and Drizella are turned back into their original selves, but dressed up as maids, much to their horror.