George and the man with the yellow hat arrive at a Halloween party--but they aren't wearing costumes. No matter--there are plenty in an old trunk upstairs, and soon George is trying on all kinds of outfits. But when he wants to look in the mirror, George finds he has to jump on the bed. Downstairs, the partygoers begin to hear noises. Then the lights go out and they hear a crash! Uh-oh. Did someone say the word ghost?