Casper Meets Wendy is a 1998 direct-to-video film based on the Harvey Comics cartoon character Casper the Friendly Ghost. The film is a sequel to Casper: A Spirited Beginning while it being the second prequel/spin-offs to the 1995 film Casper. Haim Saban, best known for creating the Power Rangers, serves as an executive producer for this movie, and his production company, Saban Entertainment, was also involved. This was the first major film for Hilary Duff, who was nearly eleven years old when this film was released. It was released by 20th Century Fox on September 22, 1998. It then aired on October 27, 1998, four days before Halloween, on Fox Family Channel.
A mysterious "spaceship" floats over a baseball game eventually revealing Stretch, Stinkie, and Fatso, The Ghostly Trio, who cause panic in the ballpark. Their nephew Casper, attempts to settle the agitated crowd, but are just as scared of him. The park empties, and Casper's uncles plan a vacation.
Meanwhile, a malevolent warlock named Desmond Spellman who believes himself the greatest warlock to have existed gets an unwelcome messaged by the Oracle in the Mirror who tells him that in the future, a child Wendy the Good Little Witch will surpass him in being the greatest witch ever. To avoid this, Spellman plans to get rid of her once and for all with the advised "Mystic Abyss". He then creates a pair of henchmen: Jules and Vincent, and assigns them to bring Wendy to him where she is living in the country with her three aunts Gert, Gabby and Fanny.
Jules and Vincent arrive for Wendy, who narrowly escapes with her aunts. To keep Wendy safe from Spellman, her aunts hide and vacation at a resort hotel which happens to be the same place in which Casper and his uncles are vacationing.
Casper and Wendy meet in a barn and, due to their nice personalities and having been bossed around by their respective guardians, they become great friends. Unfortunately, her aunts and his uncles might not get along because ghosts and witches are natural enemies. However, they are certain they'd get along if they only got to know each other. Casper tricks the Ghostly Trio to break the record for possession so that he can learn how to do it, and they possess three men at the party. Wendy convinces her aunts to go to the party to meet men. Thanks to the two working together, they meet and soon the Trio are flirting with the three witches, posing as regular women.
Though everything goes well at first, with the ghosts and witches unwittingly enjoying each other's company and finding that they have a lot in common the plan is spoiled when the possession wears off and the ghosts' real selves are revealed to Wendy's aunts who revealed their real selves as well and threaten them with magic. However, as Wendy explains to Casper, she and her aunts cannot use magic powerful enough to affect ghosts or else Spellman will be able to track them down. She begs Casper not to tell anyone about this. Unfortunately, when the Trio suspects Casper is protecting the witches, they pressure Casper into blurting out that the witches cannot use their powers, prompting the Trio to terrorize Wendy and her aunts. Wendy feels she has no choice but to cast a high-level spell on them, covering them in plaster, thus alerting Spellman's magic tracker.
Distraught that Casper broke his promise, Wendy ends their friendship. Casper soon confronts his uncles, and tells them the witches are in danger and they should help. The Trio scoff at first and refuse, but Casper reminded them that at the party the Trio showed that they actually did care about them.
After trying to escape the resort the witches are soon found by Spellman and his henchmen. After confronting the witches, Spellman explains the Oracle's prediction and, after trying to resist him, Spellman casts Wendy into the Mystic Abyss to destroy her, but Casper dives in to rescue her. Her aunts try to fight Spellman, but are not powerful enough. Yet before Spellman can turn the witches into fertilizer, a giant three-eyed monster pops up and frightens the evil warlock, turning the tables and along with Wendy's broom pushing him, causes him to fall into the Abyss himself. The monster turns out to be the Ghostly Trio, who have a change of heart and decide to help after they combine their powers to defeat Spellman. While they hold the door to the Abyss open, Wendy's aunts pull her and Casper out.
Both Casper and Wendy are weak and unconscious; but with encouragement and comfort from their guardians, Casper is restored by his uncles and Wendy is treated by her aunts. After a touching reunion between the witches and an awkward one between the ghosts, the witches thank the Trio for helping them. The Oracle then proclaims that Wendy is the greatest witch because she did something no other witch ever could; she befriended a ghost. Later, Casper, his uncles, Wendy, and her aunts all bid each other goodbye, and Casper and Wendy assure each other they will meet again soon. Before flying back home with her aunts, Wendy gives Casper a goodbye kiss and his face blushes bright red.