When two women close to a dead businessman are murdered, Nikki, Jack and Leo open his family's skeleton-packed closet.

The murders of two women in a house basement force Jack to lock horns with an old flame, while Leo wrestles with providing a second post-mortem on a baby.

As the basement women case highlights two cooperating killers, Nikki, Jack and DI Reed realise one victim was killed by a controlled sedative.

When a pub landlady is stabbed to death and her little finger cut off, Nikki is isolated in her quest to prove the husband's innocence.

When arrested and interrogated by DI Kate Warren, Alan Lane vehemently protests his innocence and insists he didn't kill his wife.

Nikki is wooed by a science minister as she and Jack investigate a murder on an eco-building project, whilst Leo finds himself trapped in a hospital siege.

Conflict brews between Leo and Nikki when he suspects her new boyfriend is involved in a 50-year cover-up, leaving Leo battling alone to expose the truth.

Human remains found on an Afghan water supply project send Leo, Nikki and Jack to the war-torn region to establish if it is a missing British soldier.

Leo develops a life-changing relationship with a charity worker as Nikki and Jack make a forensic breakthrough on their case in Afghanistan.