Jackie Lantern's Hallowe'en Revenge

Mother and Father, daughter Betsy, and son Tom, are getting ready for a local masquerade party when the Sheriff arrives with bad news. He's been sent to the farmhouse to find out "whodunnit," even though he isn't sure what it is the culprit "dun"

The family is immediately wracked with guilt, certain that one of them has committed a heinous crime. Mother and Father suspect that Tom is the guilty party, and attempt to drown him

Then Mother tries to wing Betsy with a shotgun. And Father, aping the investigations he's seen in the movies, persuades the others into making lurid confessions, including, finally, Mother's tortured admission that "I did it and I'm glad!"

What she did, it turns out, was to find Betsy and Tom in a sack at the train station many years before, and to claim that they were her own children

Her revelation throws the family into a frenzy of remorse and regret that ends only when the Sheriff receives word that he's at the wrong farmhouse, and that no one here "dun" anything after all

Relieved that their ordeal is over, the family heads off at last for the masquerade party, with Betsy dressed as a pregnant prom queen, and Tom decked out in high heels and a dress; while "Jackie" glows ever more brightly in the descending darkness