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.

Nikki arrives at a murder scene to find it's a carbon copy of a case in her past.

Nikki becomes the prime suspect after a former colleague is murdered.

A young British Muslim returns to the UK, and concerns over her intentions soon escalate.

Thomas must put his personal feelings aside as the team track down Begovic.

An ex-convict is killed and suspicion lands on a recently released child killer.

Further victims are killed and a distinctive modus operandi begins to become clear.

The shooting of a teenager in an armed police operation triggers a series of murders.

Jack leads the hunt for suspected killer Bruno, the brother of the shot teenager.

A family murdered at a picnic leads the team to the female victim's estranged husband.

As Nikki and Jack move closer to the truth, their lives are thrown into mortal danger.

When a people smuggler is found dead in the City, Nikki must delve into London's illegal immigrant community. She meets a vulnerable Syrian teen called Akka who is in need of help, putting Nikki in a moral dilemma - and the killer is still on the loose.

When Nikki, Jack and Thomas make a horrific discovery in the van, they are confronted with the work of a killer who preys on illegal immigrants. With the help of Clarissa, they must work out where the killer will strike next before more vulnerable people meet the same fate.

When a photogenic young schoolteacher goes missing, Jack and Nikki are called to the scene and quickly find themselves at the centre of a media storm. Meanwhile, Thomas fights a lone crusade for justice for a troubled young woman who was killed in puzzling circumstances.

Having found a link between the two cases, the team struggles to make sense of it. Nikki visits a disgraced former colleague who may hold the key. Thomas uncovers the bizarre truth about how Tina died.

A woman's body found floating in the Thames leads Nikki and Jack to a community on the banks of the River Lee. Three years ago a teenager called Ruth Tresize went missing from the area, leaving the locals haunted by suspicion and grief. A fresh spate of killings reopens these old wounds.

Nikki is under fire for leaking information on a suspect, and Thomas is called in to play peacemaker. Jack and DI Ashton track down the mystery witness. Before the killer strikes again, the team must uncover the true story of Ruth Tresize's disappearance three years earlier.

When an East End father and son are killed in a shocking road accident, Nikki and Jack find themselves working alongside a police officer with a vendetta. Clarissa summons her husband Max, a digital forensics expert, to help crack the case - and uncovers disturbing video evidence.

Nikki helps Becky come to terms with her trauma. Jack is paranoid that Clarissa will leave the Lyell Centre. Paul is in way over his head.

Nikki travels to Mexico to attend the funeral of Luisa, a former intern at the Lyell Centre who was murdered in a carjacking in her native country. She soon stumbles across the post-mortem report and realises that the body is not that of her ex-colleagues. Assisted by Dr Eva Vasquez and fired up with the idea that Luisa might still be alive, Nikki and Jack trace her last-known movements and are led to a farm where a cartel massacre was carried out.

A frantic Jack carries out forensic examinations on the spot where Nikki disappeared. With Thomas at the airport ready to come out and help, but still 24 hours away and no leads left to follow, Jack receives a text message containing a mysterious phone number. However when Jack calls through, expecting to hear from Nikki's captors, he is shocked at who answers the phone.

Nikki struggles to come to terms with life back home and seeks out fellow pathologist Sally Vaughan for support, only to learn she is nowhere to be found. National Crime Agency investigator Guy Bernhardt asks Nikki to help him by employing pathologist David Cannon, the chief suspect in Sally's disappearance. As Jack, Clarissa and Thomas share concerns about Nikki's wellbeing, a body found in a reservoir is linked to a murder case from 16 years previously. Return of the crime drama, starring Emilia Fox, with Julian Rhind-Tutt and Alex Macqueen.

Nikki's suspicions about David Cannon are roused further when she discovers blood in the boot of his car an with Thomas's support she takes samples to process. Does it belong to Sally Vaughn? Meanwhile, the uncovering of the body from the 16-year-old murder shines the spotlight on three people who went to the same school. Emilia Fox stars, with Julian Rhind-Tutt and Alex Macqueen.

A series of tragic events are linked to the hacking of a hospital database.

The team wonder if the hack is the only danger as they come under threat.

A US diplomat is shot dead in central London, forcing the team to work closely with the embassy and the FBI.

Nikki is still in shock as the team arrive at Matt's residence but insists on working at the Lyell, determined to help. When analysing crime scene photos and the positions of the victims' bodies, Nikki realises there is a pattern. Together, the team uncover a secret that has been held by those at the very top of the US government.

While two care home staff are chasing Kevin McDowd, a young man with learning disabilities and sociopathic tendencies, Nikki and Jack examine a fatal road accident where the deceased is Kevin McDowd's mother. The investigation led by police sergeant Button should be straightforward, but the forensic evidence suggests foul play.

The team are determined to uncover the truth about unexplained deaths of patients at a care home. They are desperate to rescue Serena and return her to safety. Unbeknownst to her colleagues in the Lyell Centre, Clarissa allows herself to be admitted to the care home in order to investigate. Her determination to find out what happened at the care home leads her to uncover a shocking truth, but puts her life in danger.

Nikki, Jack, Thomas and Clarissa are just settling down for their respective festive celebrations when they are interrupted by a call-out to a tragedy at a family home.

As the truth behind the McMorris family is revealed, the team is brought together by the conclusion of a shocking Christmas family tragedy. Reuniting with their respective families, Nikki finds her secret Santa gift is a visit from a loved one.

Fresh from her trip to the States, Nikki and the Lyell unit are called in to investigate an attack against a trans man. When two further attacks are reported, one leaving a potential witness, it becomes clear that the team is facing an outbreak of violence against the trans community.

A mistake has been made during the course of the investigation, and Thomas is targeted as a scapegoat. As frustration grows between the Lyell and the acting DCI, can Thomas rally the team to gather crucial evidence to find the killer before they strike again?

With new drugs hitting the streets, a head teacher confronts the dealers preying on his community, as the team deal with a surge in drug-related crime.

When tragedy strikes close to home, it puts head teacher Noah Taylor on a collision course with the criminals responsible. Can the Lyell team help him stop the cycle of violence?

A collection of dismembered body parts, covered in intricate Japanese tattoos, have been found in a Brighton waste dump. The team are called in to painstakingly piece them together and they search for clues to lead them to the killer. Outside of the lab, Nikki has some news she desperately wants to share with Matt.

The team struggle to find the final piece of the puzzle left behind by the murders in Brighton. At home, Nikki and Matt discuss their future together.

A car-bomb attack in a quiet suburban street brings back unwelcome memories for Jack, when evidence points to the involvement of a Northern Irish terror group, long thought inactive. As the family of the victim seek their own form of justice, Jack calls an old friend to help them find those responsible and stop the act of revenge from escalating.

During the team’s search for the killer, Jack works alongside an old friend from Northern Ireland, a fearless journalist who has dedicated her life to exposing the suspected organisation. As the team investigate further, they realise they have uncovered a complex conflict sustained by ties of loyalty, family and retribution.

Nikki is humiliated in court when a barrister accuses her of making a serious error in the case of a policeman who may or may not have been murdered. Meanwhile the team investigates the death of a medical researcher found in a canal with mysterious puncture marks on his body.

When Thomas sides against her findings on a controversial case, Nikki suspects foul play and takes steps to prove her theory. Jack and Clarissa follow a forensic trail connecting a dead researcher with a billionaire scientist and a secret testing programme.

The team find unexpected connections between the death of a former US ambassador in a plane crash and the apparent suicide of a successful businessman.

The team discover a connection between the plane crash and a sinister online forum. Meanwhile, Matt is grieving for his friend, putting his relationship with Nikki under strain.

When the body of a missing teenager is found in a field near his village, Nikki and the Lyell team must determine whether the killer is a stranger or a local.

Investigating the murder of missing teenager Jason Forbes, Nikki and the Lyell team are pressured by police officers who are keen to secure a conviction.

A woman's body is found on railway tracks in London. When the post-mortem reveals signs of domestic violence, it brings back troubling memories for Nikki.

When the team's search for Jenny's killer hits a wall, her friends at the women's refuge seek answers. Meanwhile, Thomas makes some friends in high places.

When a skeleton is found in concrete, the Lyell team must investigate a suspicious death dating back 20 years.

The team's investigation leads them to a mysterious cryogenics facility and the discovery of another suspicious death.

Thomas performs a post-mortem on a soldier who died in military training. His investigation takes a turn when he discovers traces of a possible nerve agent.

Jack is rushed to hospital after collapsing at the scene of a car crash. As he fights for his life, the team must identify the poison to save their friend.