The "World Holiday Commission" proposes to cancel Halloween and remove it from its annual holiday calendar due to low sales of candy and costumes. Eleven-year-old Harold Owen Ween sets out to stop the Commission before it’s too late. During his travels, Hal meets a trio of recently unemployed and good-natured monsters whose very livelihood depends on the survival of Halloween. It isn’t long before they join Hal and the audience on their quest to save the holiday from extinction.
With a script by Joe Pospisil and songs by Howard Beckerman, Halloween at the Belvedere was commissioned by the Central Park Conservancy and performed outdoors at Belvedere Castle for four Halloweens in Central Park. The Patchogue Theatre revival of the show was "Live in the Lobby," under the title Boo! and included time for the children to meet and speak with the cast of comic actors after each performance.