When Jane Hayes returns to her home one night she hears an intruder upstairs, but PCs Bradley and Bellamy find only her cat when the come to investigate. But Miss Barker, who worked for the previous owner of the house, can tell a story of a servant girl, who is said to haunt the manor listening for the cries of her baby. Jane Hayes is pregnant and due any day and the next night she hears a baby crying and sees a cradle rocking in the nursery. Penny Craddock is organizing the Christmas dance and persuades Jane's husband Graham to emcee the event. They will stage a dancing competition and Greengrass promises to provide them with a trophy for a small charge of course - besides taking bets on the outcome.