DS Stuart Turner is horrified to learn that his friend and driver, Trevor Jones, is drug dealer The Postman. Cocky Trevor tells Stuart that he’s been putting money into his account and has incriminating photos of him, which could implicate Stuart in the drug deals. Trevor tells Stuart he’s now his inside man at Sun Hill.

CID arrive at a house where they suspect ‘The Postman’ is about to do a deal. As they wait to capture him, they are surprised when two men leave the house and drive off. When a search of the house reveals that the drugs have been flushed away, DI Neil Manson concludes that there’s an informant on the team…

Later, DC Jo Masters confronts Stuart, who confesses everything. Jo’s furious, but agrees to help him arrest Trevor and save his job. Stuart heads to Trevor’s office with a hidden tape recorder and gets Trevor to admit to blackmailing him. But when Trevor knocks Stuart out, it looks like his problems are far from over.