Living under the care of his uncles: The Ghostly Trio, Casper has been letting them push him around and making his afterlife miserable by having him do chores for them while they are scaring "fleshes" for their amusement. While deciding to go they are on vacation, Casper meets with a good little witch girl named Wendy, whom she and her bewitching aunts are on the run from an evil warlock: Desmond Spellman who attempts on destroying her after discovering that she will be a greater witch than him. Like Casper, Wendy is a kind witch who also has her relatives mistreating her. The two become good friends as they discover that ghosts and witches are each other's worst enemies, so they come up with a plan to make their elders pair up to one another. Once Desmond comes into town, he determines to destroy Wendy at once. It is now up to Casper as he must get the courage to convince his uncles to help him to save his friend and her aunts from the villainous warlock.