UCOS reopen the thirty year old murder of porn king Jim Hockney when his daughter Sara reveals that a DNA test proves she is not his daughter. Her mother Jane cannot provide any answers as she and Jim both had several sex partners. Jim's girlfriend at the time, singer Angela Gold, was charged but acquitted of the murder and now seems to have disappeared. Brian's replacement Dan Griffin arrives, albeit late and is initially treated with hostility by Gerry, who thinks he is a spy. Nonetheless Dan tracks down Angela though in the meantime Sandra learns that Jim's brother Colin sold Jim's porn empire very shortly after his death to his main rival Gavin Reason. Furthermore Jane and Gavin were lovers, Gavin proving to be Sara's father though he was unaware at the time. However it is Gerry's collection of some of Jim's old films, supposedly confiscated by Vice Squad, that identifies the murder weapon and leads to the culprit. The case closed the team watch Angela perform at Ronnie Scott's Jazz Club.

The blood-stained clothes of Simon Belgrade are found in Epping Forest, where he disappeared five years earlier whilst out for a run. Frank Miles, Simon's father-in-law and employer, has a history of violence and his daughter Becky, who was heavily pregnant with Simon's child when he disappeared, seems scared of him. She does not want to believe her husband is dead and nor do his mother Eliza and brother Tim, who portray Simon and Becky as the ideal couple. However Simon's friend Dom and his ex-wife Lois tell the team that Simon and Lois were having an affair, as were Dom and Becky. Simon also had a string of failed businesses behind him and was blackmailing Frank over tax evasion, but with no money taken from his account and no passport it seems unlikely that he skipped the country. An examination of a film showing Dom and Simon's childhood haunts in the forest leads to discovering Simon's fate whilst Dan helps Sandra cope with the anniversary of her father's death.