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.