Former colleague Sam Ryan calls upon the team after the health secretary is assassinated, but as the investigation progresses, Nikki fears uncovering the truth will put the entire Lyell team in danger. Meanwhile, murders continue to happen, and each case seems to carry with it a secret from each team member's past.

Still reeling from the sudden death of Dr. Thomas Chamberlain and the shock departure of colleague Clarissa Mullery, Nikki and colleague Jack Hodgson returns to the Lyell Centre. A case at a high-security prison stirs disturbing memories for Nikki. Recruit Adam causes friction with his impetuous desire to impress. Forensic ecologist Simone's unique knowledge helps solve the murder of a promising young boxer. And Nikki suspects a body donated to medical...