Nick Pitt

Meet handsome Archie MacDonald, a reluctant young Scottish laird torn between his trendy London life and the call of his wild Highland ancestry. Tricked into returning to Scotland by his eccentric father and dotty mother, Archie discovers he is now the Laird of the decaying family estate, Glenbogle.

The team is approached by a support group of survivors from a recent train crash. What caused the tragedy, and what is the identity of the unidentified Body 21? When the mysterious body is named, Harry, Nikki and Leo get closer to finding out what caused the train crash - with tragic consequences for one of the heroes of the disaster.

1917. Michael is taken prisoner, and Joanna has some big news for Tommy.

Sam Ryan embarks on a journey home to Northern Ireland when the team is called out to investigate the discovery of the bodies of two men killed by paramilitaries twenty years ago and finds that their secrets live on in the new corridors of Belfast power. Then as Sam struggles to find reconciliation with her estranged son, the investigation takes a darker turn as she makes some discoveries about her father's past.

1918. As peace terms are negotiated and their families wait anxiously for news of their return, Tommy and Michael are still on the front line.

Harry is called out to a death at a racecourse where a jockey's horse crushed him to death.

Now Sam has left, Leo is faced with the decision of whether to take over her job; meanwhile he and Harry clash over an investigation into an outbreak of disease among schoolchildren on the South Coast. Then together they investigate an apparent case of Munchausen by proxy and race against the clock to prevent a potentially fatal environmental disaster.

A young woman falls to her death off a high-rise office building in London; it's revealed she was pregnant and taking cocaine. A black male athlete is murdered by his brother; initial signs suggest suicide by hanging, the actual cause of death is a high dose of Clenbuterol injected into his back.

Sam and Leo are on opposing sides of a high profile court case at the Old Bailey, in which two Sikh brothers are found dead in a police cell. Leo believes that the brothers were killed in custody by the police but Sam thinks that one brother killed the other before taking his own life.

Sam uncovers the crippling truth about her involvement in a case 13 years ago, in which a man was wrongfully imprisoned following the murder of his wife. After a string of new murders in which all the victims were linked to the original case, Sam realizes that she herself is in danger.