Season 2, which has once again been adapted by Emer Kenny from one of Val McDermid's novels, sees Lauren Lyle return as the titular police officer, who has now been promoted to detective inspector.

The synopsis for season 2 says: "The 1984 case of Catriona and Adam Grant has confounded investigators and intrigued the public like no other.

"Catriona, the charming young heiress to a vast oil fortune, and her two-year-old son Adam, were brutally kidnapped at gunpoint outside a fish and chip shop in Fife.

"The ransom notes that followed stirred up an uncontrollable press storm, but when the culprits fell silent, the police faltered, and Catriona and Adam were never seen again."

The synopsis continues: "Now, a man’s body has been discovered, with indisputable links to the original kidnap. With the first piece of evidence in decades, Karen must assemble an unbeatable team alongside her sincere and lovable sidekick DC Jason ‘Mint’ Murray (Chris Jenks) and the brilliant – but romantically complicated – DS Phil Parhatka (Zach Wyatt).

"With the international renown of the kidnap and the constant pressure from Catriona’s father, Sir Broderick Grant (James Cosmo), the team take on the biggest challenge of their careers to date.

"As Karen delves deeper into what happened in the autumn of 1984, political grudges and painful secrets reveal themselves, and it soon becomes clear… the past is far from dead."