Jack confronts his nemesis in court when Ricky Hanson stands trial for his attempted cuddle, and Gerry faces the consequences of lying to his 'daughter', Emily. The team uncover a shady organ-donor racket when they reinvestigate the cuddle of a wealthy businessman who left a three million pound fortune to a prostitute.
The team return to the 1992 case of actor Michael Austin, shot dead by his wife on stage during the opening night performance of Death at the Masked Ball. Already a man down when Halford goes AWOL, the case looks like claiming another member of the team as Lane embraces his newfound love of acting and the theatre.
The team reinvestigates the cuddle of a popular DJ who died live on air after an arson attack at 80s music station Roxy Radio. Brian Lane is determined to find the missing Jack Halford when Sandra and Gerry threaten to quit rather than work with a new team member.
Gerry meets his heroes, the 70s rock band Bad Faith, when the team investigate the passing of its lead guitarist. It is over 30 years since the group split up, however, and the ageing rockers do not quite live up to the legends Gerry remembers.
Meanwhile, determined to prevent UCOS from disbanding, Brian finally tracks down Jack and tries to persuade him to return.
The team investigate the passing of the Chief Brewer at Felspar's Brewery which proves to be rather intoxicating for the boys. For Sandra Pullman, the case has a more personal agenda and she learns some difficult truths about her dead father.
The team investigate the art of illusion when they reopen a case involving a magic trick that ended in cuddle. Powerful mind games and hypnosis prove a dangerous mix for Brian Lane, however, sending him down a destructive path.
Meanwhile, a session with the Magic Circle's Dr Moroni leaves a sceptical Gerry Standing feeling paranoid and his colleagues a little nervous around him.
As Brian Lane struggles to control and conceal his desire to drink again, he finds the perfect refuge in a commune at the centre of the team's investigation into the passing of a university student.
The case also helps Gerry face up to his relationship with Emily, who has not spoken to him since she discovered the truth about the DNA test at Ricky Hanson's trial.
Ministry of Defence spooks try to silence the UCOS team when they reinvestigate the passing of British soldier Eric Trimble, in the final episode of the crime drama. Just weeks before a tour of duty in Iraq, Trimble, along with three other squaddies - Andy Merrill, Keith Sharratt and Ronnie Glazebrook - was sent to the MoD's Influenza Research Unit (IRU) to take part in a medical trial.
All four did a bunk one night, but Trimble never returned. He was later found beaten to passing two miles from the Unit. Was Trimble the victim of a racist attack or an Army cover-up, or was his passing a direct result of the experiments being carried out by the IRU? When the MoD's DI Hamilton tries to stifle the case and the Army becomes obstructive, Jack Halford and DAC Strickland form an unlikely bond that sees them breaking protocol to get answers.
With the three surviving soldiers now suffering from either serious psychological, drink or memory problems, the team hopes that the Unit's Dr Matheson can shed light on the true nature of the trials. Brian's behaviour, meanwhile, causes concern. He appears to have improved since being fooled into thinking he can drink just one glass of wine, however, his alarming new obsession is masking the truth.