It's Christmas, and things are looking good at the Slocombe house. Thea's daughter Jessica has come to stay, much to her stepdaughter Stephanie's delight. But then things take a turn for the worse. A local family, the Frowses, find themselves increasingly harassed by an aggressive landlord. When Beverley Frowse goes missing, Thea and Stephanie both feel they should do their best to help her husband and son to solve the mystery. Christmas Day arrives. There are presents, a turkey, and general goodwill, despite Thea's suppressed hankering to be involved in events at the Frowses' house, where a dead man has been discovered…