The award winning and critically-acclaimed crime drama returns for another series of dark, gripping murder mystery investigations. In the six stories, DSI Boyd and his Cold Case Squad enter the visceral worlds of international terrorism, private military contractors, the penal system and sex offenders, Navajo rituals, people trafficking and neo nazi politics to close more previously unsolved cases. Boyd's son, missing for seven years, also makes a surprise reappearance.

Guest stars:

• Beatriz Batarda
• Justine Mitchell
• Michelle Forbes
• David Schofield
• Ruth Gemmell
• Michael Maloney.

Episodes Comprise:

1: Missing Persons: Part 1
2: Missing Persons: Part 2
3: Sins: Part 1
4: Sins: Part 2
5: Duty and Honour: Part 1
6: Duty and Honour: Part 2
7: Skin: Part 1
8: Skin: Part 2
9: Wounds: Part 1
10: Wounds: Part 2
11: Pietà: Part 1
12: Pietà: Part 2.