The mysterious death of a wealthy confectionery firm owner plunges Nikki, Leo and new recruit Jack Hodgson into a murky world of corporate subterfuge.

When two women close to a dead businessman are murdered, Nikki, Jack and Leo open his family's skeleton-packed closet.

The murders of two women in a house basement force Jack to lock horns with an old flame, while Leo wrestles with providing a second post-mortem on a baby.

As the basement women case highlights two cooperating killers, Nikki, Jack and DI Reed realise one victim was killed by a controlled sedative.

When a pub landlady is stabbed to death and her little finger cut off, Nikki is isolated in her quest to prove the husband's innocence.

When arrested and interrogated by DI Kate Warren, Alan Lane vehemently protests his innocence and insists he didn't kill his wife.

Nikki is wooed by a science minister as she and Jack investigate a murder on an eco-building project, whilst Leo finds himself trapped in a hospital siege.

Conflict brews between Leo and Nikki when he suspects her new boyfriend is involved in a 50-year cover-up, leaving Leo battling alone to expose the truth.

Human remains found on an Afghan water supply project send Leo, Nikki and Jack to the war-torn region to establish if it is a missing British soldier.

Leo develops a life-changing relationship with a charity worker as Nikki and Jack make a forensic breakthrough on their case in Afghanistan.

Premiership footballer Isaac Dreyfus finds his career in tatters after a sex tape links him to the brutal murder of a young woman, threatening to destroy both his reputation and marriage. He is desperate to prove his innocence, while Adam Freedman turns to a mysterious source for help to avenge the murder of his wife and child. Nikki finds it hard to deal with Leo’s death following the arrival of the new Lyell Centre boss, pathologist Thomas Chamberlain.

Isaac Dreyfus fights to prove his innocence, whilst Adam Freedman turns to a mysterious source for help get revenge for the murder of his wife and child. Nikki questions the motive behind the murders and a re-examination of the Freedman crime scene leads Jack to make a shocking discovery.

Nikki finds her professionalism being brought into question during the case of convicted killer David Bennetto, who was jailed for the murder of two gay teenagers. Thomas attempts to save The Lyell Centre’s reputation.

Thomas is under increased pressure from DI Rachel Klein and the Home Office as he battles to save the Lyell Centre's reputation. Peter Masham makes an unlikely deal with Bennetto's brother-in-law. Jack and Clarissa finally uncover the true identity of murder victim Byron Lee.

Nikki and Jack head to Scotland to help earnest rural detective DS Jason Ross investigate the chilling murder of a lap dancer found in a remote forest. In their search to find a suspect, the team clash with rogue city detectives DS Mike MacNeil and DI Simon Laing. But as more human remains are unearthed in the forest, it becomes horrifyingly apparent that a dangerous serial killer is at large. News of the murders unsettles new mother Sarah, who is harbouring a dark secret from her partner Steve.

Nikki, Jack and DS Ross are feeling the pressure to close the net on a serial killer abducting young women. Concerns increase about missing Sarah, and solving her mysterious disappearance becomes an urgent priority for the team.

After the body of a pregnant Northern Irish girl is found, Nikki and Jack need to locate the baby that has been snatched from her womb. Thomas discovers the girl’s connections to a criminal underworld.

Martin is found dead in suspicious circumstances. Nuri becomes increasingly desperate to locate the missing drugs, with some tragic consequences. Nikki attempts to help a grieving William come to terms with his daughter Alice's death and his missing baby granddaughter.

Jack becomes involved in an investigation into the murder of a 15-year-old girl owing to his personal connection with the prime suspect. Thomas needs to clear up the conflict of interest.

Jack's world has been blown apart following the discovery of Hannah's dead body. Nikki manages to find out the truth behind Jack and Ryan's strained relationship. Thomas thinks about hiring forensic scientist Helen as Jack's permanent replacement. Christy Nash is scared for the future of his marriage and business after DI Carter finds out abouts of his relationship with 15-year-old Katie.

Nikki and Jack strive to track down a sniper at large in London and stem a public crisis.

Nikki and Jack investigate links between the victims to close the net on the killer.

Nikki and Jack investigate a man killed by a train on the London underground.

Nikki helps high-flying DI Luke Nelson unearth painful childhood memories.

A suspected paedophile is found murdered in a children's playground.

Nikki, Jack and Thomas focus in on Lizzie's movements on the night of Barge's murder.

The nanny of a Russian oligarch is killed in a botched assassination attempt.

A young woman working for the Doshis is found dead in Maksim's apartment.

The Lyell team are under pressure to catch the killer of an admired Essex police officer.

When the body of local criminal Jason Simons is found, the course of the case is changed.