A new murder victim forces the team to consider whether a notorious serial killer has resurfaced after 20 years, or if they are dealing with a copycat.

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.

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?

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?

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.

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.

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.

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.

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”.