When snobby Claire Brewster excludes Lydia and her friends from a popular kids' Halloween party, Lydia decides to have one of her own. But when Delia takes over the planning, it looks like disaster is imminent until Beetlejuice -- as Mr. Beetleman -- offers his catering service. Armed with party supplies from the Neitherworld, he's ready for anything...except the discovery that one of his decorations, Party People in a Can, shouldn't be used during a full moon. He and Lydia must hunt down the missing Party People before they wreak havoc on all of Peaceful Pines.