Larry the Zombie and Fred the Mummy are feeling out of place on Mischief Night, as they are usually the ones scaring humans, not being left out. Fred, in particular, is desperate to be rid of his mummy curse and become a regular human again. Enter Boo the Bogeyman, who suggests they seek out Goul, a magical tree who might be able to help them.
The trio sets off on a quest through Halloween Town, encountering a host of quirky and spooky characters along the way. They meet a witch who tries to cook them up in her cauldron, a group of mischievous ghosts who play pranks on them, and a talking pumpkin who gives them some valuable advice.
Finally, they reach Goul, who offers to lift Fred's curse in exchange for a favor. The Halloween Family must protect Goul from a group of evil trolls who want to chop it down and destroy its magic. Larry, Fred, and Boo team up with some new friends to take on the trolls and save Goul.
In the end, Fred's curse is lifted, and he becomes a regular human once again. The Halloween Family celebrates with a spooky party in the town square, and Larry and Fred feel like they finally belong among the other creatures of Halloween Town.