The Lords and Ladies of Harmony Hall are gritting their teeth for another gloomy, guest-less Christmas gathering, hosted by the dour Dukes of Grinchester and Glowermore. But when their estranged Aunt Agatha (whom they never invite) sends mysterious word to expect an uninvited guest (a thief), a host of madcap mishaps ensue. Who’s the thief? What’s been stolen? The game’s afoot!