She is first seen with her widowed father, Dr. James Harvey, a paranormal therapist moving into the Whipstaff manor as their new home and meet Carrigan Crittenden and her attorney, Paul "Dibs" Plutzker for the first time. She then discovers the three beds that belong to the ghostly trio and Casper's uncles, Stretch, Fatso and Stinky and she first meets Casper, at first, she becomes frightened, but Casper befriends her, saying that he is a friendly ghost and Casper begins to befriend his new mortal guests, Kat and Dr. Harvey and his uncles. She then finds Casper's bedroom and helps him remember his childhood as they found an old shed and discover that Casper's father died from a fatal illness. She then finds a newspaper article describing how Casper's father created a machine called the Lazarus which allows to bring his son back to life. she and Casper enter a secret passage that leads down into the laboratory basement of Casper's father, but Carrigan and Dibs discovered a vault as they realize that the treasure must be there. By inserting a formula to bring someone back to life, Carrigan and Dibs steal the formula in order to kill themselves and rob banks as ghosts and become alive again in order to become rich, but after they find the formula, Dibs turns against Carrigan as he lets her fall to her death, but Carrigan is now a ghost and tries to kill Casper and Kat as she throws Dibs out the window and Dibs falls to his death since she doesn't need him anymore, but Casper reveals to Carrigan that the treasure is actually an autographed baseball signed by Duke Snider as Carrigan is destroyed. As Dr. Harvey and the Ghostly Trio appear, Kat discovers that her father is now a ghost after he died by falling down a manhole and no memories of her, but Casper decides to end up being human again by allowing the Lazarus to revive Dr. Harvey. The Halloween guests arrive for the party, but the Ghostly Trio scare them as Casper sees Ameila's spirit and grants him a wish to spend only one night being alive temporarliy. Towards the end of the film, Kat then kisses Casper as Casper is reverted back into a ghost as Kat begins to have romantic feelings for him and Casper becomes attracted to her as Casper scares the party guests away and the six begin to celebrate Halloween themselves.