Casper accidentally finds himself in the world of the living after failing to show up for ghost training and befriends a young boy who teaches him the ways of a ghost, while a ruler from the other world attempts to bring him back.

When Casper failed to show up at the Ghost Central Station, he instead finds himself in the world of the living where he befriends a 10-year-old boy named Chris Carson who loves ghosts and the supernatural and has a workaholic father named Tim who spends little time with him as he attempts to tear down an old mansion to update the town. Casper also meets with the Ghostly Trio who, along with Chris, are willing to help him become a better ghost. Meanwhile, a monstrous ghoul named Kibosh, the head of the Ghost Central, discovers Casper's absence and sends out his assistant, Snivel, to find him and bring him back at once.