Wendell, Floyd, and Mona can't seem to avoid trouble, particularly on Halloween! It all starts when a black cat crosses their path while they're walking home from school, which seems to cause all their costumes to go awry. Then, while trick-or-treating, some of their neighbors surprise them with tricks instead of treats. As if that weren't bad enough, a pack of nasty witches is chasing them through the neighborhood, making fun of their costumes! Will the kids be able to save their Halloween from disaster?