After Sangers Telephone Service is robbed, CID once again through their weight around at the Ashfordly station as they suspect a local gang are responsible, but Blaketon is convinced worker Tony Mowbray has performed an inside job because he has a history of crime and becomes determined to crack the case before the arrogant detectives and show them that the Ashfordly station are more than capable of fighting crime. Meanwhile, Jo is concerned for one of her pupils, Dennis Cross, who hasn't attended school for days. She and Maggie pay him a home visit and are horrified to find his mother dead - and Dennis nowhere to be seen, whilst Greengrass makes a dodgy deal with a butcher, whose factory is subsequently robbed.