第二次世界大战中的一次轰炸任务意外击中一所满是孩子的学校，几名哥本哈根居民的命运因此交织在了一起。本片改编自真人真事。

丹麦悬疑犯罪片，该片刷新丹麦国产片票房纪录，是系列电影《悬案密码》的第四部，也是最终章，《悬案密码》系列改编自丹麦小说家尤西·阿德勒-奥尔森（JussiAdler-Olsen）的同名小说，

In Nightwatch the sequel, Emma, a medical student, takes on a nightwatch job in the forensic department. And it is no coincidence. Since the fatal night-30 years earlier, when psychopathic inspector Wörmer almost killed Emma's parents, who were saved at the very last minute by their friend Jens, her family has been haunted by this horrific memory. Her mother Kalinka, actually committed suicide when Emma was 10 and her father Martin is still the shadow of himself. 　　The young woman decides to investigate what happened in her parents’ past. Upon meeting with Wörmer, Emma wakes him from his coma, and unintentionally initiates a bloody revenge on all of those who sealed Wörmer’s destiny.