Following the deaths of Georgia and the witness it is Steve who gets a grilling as to the police presence at the hospital whilst Lindsay is accused of attacking her neighbour, which she denies. Steve discovers that a nurse on the witness's ward, Claire Tindall, was threatened into giving the killer access by a man she knows as Joe, but whom she is unable to identify. Lindsay continues to search for vanished teenager Carly Kirk and Kate is drafted in as her assistant - in reality a move to try and get Lindsay to admit her guilt - but Lindsay sees through the ruse. After Kate's cover is blown Lindsay is questioned again and claims that she rang the hospital to ask that the witness exonerate her but she is disbelieved and Hastings arrests her for conspiracy. At her interview she points out that Steve visited Claire unofficially and Hastings has financial problems and a broken marriage that could make him just as culpable but she is nonetheless held in custody. Meanwhile DCC Dryden finds himself in the frame for a driving offence supposedly committed by his wife.

Danny's armed-response unit come under increasing scrutiny as AC-12 feed Kate information to help her crack their story. Steve makes a shocking discovery, then his own past catches up with him.

DS Steve Arnott believes there is a dark secret in Danny Waldron's past. Then the spotlight falls on his questionable conduct in a previous inquiry - the Lindsay Denton case.

When DCI Roz Huntley captures a serial killer, Forensic Coordinator Tim Ifield alerts AC-12 to a possible miscarriage of justice.

A dismembered body is discovered, and worries grow when Roz fails to report for duty. After further questioning of Michael Farmer unearths crucial new information, AC-12 challenge the case against him.

As shocking new evidence is unearthed, AC-12 step up their investigation into the case against Michael Farmer.

The discovery of new forensic anomalies appears to provide AC-12 with a major breakthrough. Meanwhile, Nick Huntley comes under scrutiny.

AC-12's future hangs in the balance after Hilton bars them from investigating Roz Huntley. But Roz's problems are building closer to home.