The doorway to the great beyond has opened at a children's birthday party long enough to possess four-party clowns. Driven by the desire to bring their master, the Great Shadow Overlord, into this world, they embark on a bloody quest to find the three keys of the ancients to open the doorway permanently. The only one in their way is the children's paranormal television show host, Mr. Jacobs. Time is running out, though, as these party clowns of doom are getting closer to their final objective, ending all life in this world and ruining Mr. Jacobs's zombie-making vacation to Nantucket.