When Danny and Wendell find an injured bat at the neighborhood pool, they take it to Mexico where Danny's cousin, a bat specialist lives, but once there Danny is snatched up by a giant bat monster, and it is up to Wendell to save him.
Not only must Danny and Wendell trick-or-treat with skeptical classmate Christiana, school bully Big Eddy dares them to enter a haunted house on Halloween night, where they may have to sacrifice their candy to a ghost.