Celia Gilmour is calling at her sister Eileen Bayne when she scares off two burglars, Jimmy and Danny. PC Ventress inspects the place, but finds neither her nor her husband Tommy at home and nothing unusual. When Tommy Bayne returns PC Bradley and PC Bellamy check the house again and find Eileen Bayne dead in a locked room on the 1st floor. Meanwhile Greengrass is on to another scheme of Jimmy and Danny's. They clog up people's drainpipes and then offer to clean them again for £15 and Greengrass wants to clean up before they do. Aunt Mary gets a visit from Bill, an old friend who offers her a position as manager of his hotel in Sidmouth. Sergeant Craddock is going on a short leave to teach new police cadets at the training centre and wants a completely clean slate before he goes.