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 pieces together the mystery of a man found dead on the shore of the Thames, while the life of a disgruntled criminology professor begins to unravel.

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?

A mummified corpse, undiscovered for a year, is found in a flat. The team strive to uncover its identity and are drawn into a murky world of drugs and botched plastic surgery.

Nikki and Jack work to uncover the truth surrounding a death and consider if it’s linked to their original body. Meanwhile, DI 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, whose young pregnant wife desperately hopes is still alive. Nikki and Jack piece together the perplexing crime scene and find it poses more questions than it answers.

Nikki has a breakthrough and edges ever closer to the truth as they confront a key witness. Who can the team believe and, more importantly, who can they trust?

The Lyell are called to King's Cross Station Museum, where they discover the bodies of eight victims entombed below. With the knowledge that a prolific serial killer was operating in London nearly 20 years ago, Nikki and the team know this will be a case like no other.

There are further twists ahead for Nikki, Jack and the team as they work with the police to explore multiple avenues to solve a 20-year-old case.