高级督察Amy Silva（Suranne Jones饰）和警督Kirsten Longacre（Rose Leslie饰）再度携手侦破新案，此次她们被派往偏远的北极研究站，一名英国秘密特种部队成员在此遭枪击身亡。 在极地气候变化引发的能源资源争夺战背景下，Amy和Kirsten必须抓住凶手，并化解一场潜在的国际冲突，而她们的职业生涯和感情关系都将面临考验。

　　After her bittersweet success in series one, Karen has been promoted to Detective Inspector and seemingly given the authority she has long been fighting for. Just as she’s getting into the swing of her powerful new role, she is assigned an infamous unsolved case that will put her under intense scrutiny; from her boss, from the media, and ultimately, from sinister forces that would rather the past stayed in the past.　　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.　　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’ and the brilliant – but romantically complicated – DS Phil Parhatka. With the international renown of the kidnap and the constant pressure from Catriona’s father, Sir Broderick Grant, 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.

在第一季中苦乐参半的成功之后，凯伦被提升为警探，似乎获得了她长期以来一直争取的权力。就在她逐渐适应这个强大的新角色时，她被指派去处理一桩臭名昭著的悬案，这让她受到了密切关注：来自她的老板、媒体，以及最终那些希望过去就此结束的邪恶势力。