The new season returns to Larvik on a seemingly idyllic summer evening at the Greenwood family. But the following morning, a hotel employee is found murdered, and a six-year-old British boy, Clifford Greenwood, has disappeared without a trace.
The family receives a ransom demand and cryptic messages from the kidnapper, and when family secrets are revealed, Wisting suspects that there may be a personal motive behind the disappearance. There is also enormous international pressure on Wisting and the team to solve the murder and find the boy before it is too late.

《失眠》讲述了事业有成的女强人艾玛-艾薇儿（Emma Averill）在 40 岁前两周因睡眠不足而担心自己失去理智的故事。

　　她的母亲在同样的年龄也有过类似的经历，在 40 岁生日的那天晚上精神崩溃。但即使在重温母亲的经历时，艾薇儿也相信可能是其他力量在起作用。

　　她的母亲突然受伤住院，与她疏远的妹妹毫无征兆地回来了，她感觉自己似乎被人监视着。只有调查痛苦过去的真相，她才能找到现在的答案。