Sergeant Craddock has been promoted and a new sergeant is expected at Ashfordly police station. His name is Dennis Merton and he is an ex-CID. From their patrol car PC Ventress and PPC Nicholson spot the disqualified driver Paul Rogers going in the opposite direction in his car after seeing his girlfriend Sandra, but Rogers denies having been driving when they confront him. His father Ken Rogers has had CID chasing his tail for years, and by going after Paul the Ashfordly police land themselves in the middle of a major CID investigation. David is out of form from sitting in the taxi and wait for customers. Vernon Scripps supervises David's training and spots the talented boxer Jeremy Purves. Scripps has high hopes for his new protégé, but despite his talents Purves lacks the deciding punch.

PC Bellamy takes over one of Alf Ventress' old contacts, Vic Smalley. From him he learns about Ray Craven, who is flush with money and it is not through taking sheep to market, which is his official business. But Bellamy does not exactly make the top of Sergeant Miller's charts when the police make a raid on one of Craven's lorries and find only sheep. When Gina tidies up in her guest Derek Ford's room she discovers that he works for the Inland Revenue. He is "on tour" in the area and Vernon Scripps is next on his list. In fact Scripps owes so much in back tax that he will never be able to pay it and he decides to do something drastic. Too late for him Oscar Blaketon discovers that Ford is a fraud with no connection at all to the Inland Revenue.