Emilia Fox returns as Dr Nikki Alexander. Still reeling from the sudden death of Dr Thomas Chamberlain and the shock departure of colleague Clarissa Mullery, Nikki and colleague Jack Hodgson return to the Lyell Centre. A case at a high security prison stirs disturbing memories for Nikki. New 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 science may not have died from natural causes after all.