In Series 27, pathologist Dr Nikki Alexander (Emilia Fox), forensic expert Jack Hodgson (David Caves) and their dedicated team must help the police solve some of their most chilling cases yet: a body found in an abandoned church sparks fears that a serial killer has resurfaced after twenty years, death terrorises a university campus and no one is safe, a mummified corpse is uncovered - seemingly forgotten by everyone, multiple bodies are found entombed beneath a train station in a makeshift mass grave, and the Lyell is infiltrated by a malevolent force.

As the team use their expertise to unlock the truth, they are tested to their very limits. Gabriel seeks advice from Jack in an unexpected way, and lets down his guard at work with devastating results. Velvy tries to do the right thing by his family, but at great cost to himself. Cara navigates London student life, making friends and enemies along the way. She impresses Jack when she undertakes work experience at the Lyell, and is forced to intervene when she makes a shocking discovery about Velvy. Nikki and Jack deal with one of the most difficult cases of their career and their relationship becomes stronger than ever.

Episode 1: Effective Range Part One by Jim Keeble and Dudi Appleton

Nikki and Jack investigate a murder bearing all the hallmarks of a notorious serial killer. When Nikki meets Charles Beck, the pathologist who conducted the original post-mortems, she discovers his wife was the suspected fifth victim of the serial killer, but nobody believes him when he claims he knows where to find her body.

Episode 2: Effective Range Part Two by Jim Keeble and Dudi Appleton

When a woman’s body is removed from a reservoir, Nikki performs the post-mortem and confirms she is the deceased wife of pathologist, Charles Beck. Jack and Velvy discover new evidence that leads to a surprising arrest as Nikki continues to seek the truth about notorious serial killer Calvin Dunn.

Episode 3: Grievance Culture Part One by Tim Prager

The team work a suspected suicide but the investigation raises more questions than it answers. Gabriel has an exciting new opportunity, both professionally and personally, and enlists Jack’s help. When a disgruntled professor of criminology is passed over for promotion, events take a truly sinister turn and the interview panel begin to be targeted. Could a member of the Lyell be next?

Episode 4: Grievance Culture Part Two by Tim Prager

Events continue to spiral at the university and Cara becomes collateral damage. The riddle of the body in the Thames is solved. A breakthrough in the Cherry case is received from an unlikely source, but will the team get there before it is too late?

Episode 5: Invisible Part One by Tim Prager

The team investigate the body of a woman found in a flat after being dead for a year. As they seek to find out the truth of her identity and what happened to her, they must draw on all of their forensic and pathology knowledge to solve the case. Even if the world had forgotten her, the Lyell are determined that she must get justice.

Episode 6: Invisible Part Two by Tim Prager

Nikki and Jack work to uncover the truth surrounding Roy’s death and consider if it’s linked to their original body. Meanwhile, D.I. Torres searches for a stalker and Cara is shocked at Velvy’s living conditions. As the case comes to a head, there are surprises afoot for the team.

Episode 7: Death By A Thousand Hits Part One by Ed Whitmore & Tracey Malone

The team investigate the death of a Burmese man on a deserted beach, as his young pregnant wife desperately hopes he is still alive. Nikki and Jack piece together the perplexing crime scene and find it poses more questions than it answers.

Episode 8: Death By A Thousand Hits Part Two by Ed Whitmore & Tracey Malone

Nikki makes a breakthrough but can the team believe everything they are told? The Lyell is compromised in an unexpected way, as the team strive to find out who the man on the beach was and why he was killed. In a dark and chilling story, they must unite to discover the truth, and above all, trust no one.

Episode 9: King’s Cross Part One by Ed Whitmore

The Lyell are called to a museum outside King’s Cross Station, where they discover the bodies of eight victims entombed below. With the knowledge that a prolific serial killer was operating in London nearly twenty years ago, Nikki and the team know this will be a case like no other.

Episode 10: King’s Cross Part Two by Ed Whitmore

Nikki continues to try and identify the last of the remaining bodies in an effort to uncover any connections and find motive, while Jack and the police begin to look into several two-decade old missing persons cases which might reveal the identity of the man dubbed “The King’s Cross Serial Killer”.