When Katarina Huss starts as a police officer, she must learn to cope with the hard everyday life on the streets of Gothenburg. At the same time, her colleagues seem to be hiding something and soon she is drawn into a tangle of corruption and betrayal.

The Section de recherches is a special unit of the Gendarmerie nationale, responsible for the most complex cases. In Bordeaux (from 2006 to 2013) and then in Nice (since 2014), child abductions, disappearances, heinous or sexual crimes are the daily lot of the investigators in this research unit. In the search for witnesses, the team is authorised to extend its investigations beyond France's borders.

哥德堡（Gothenburg）接连遭遇一系列火灾。艾琳·胡斯（Irene Huss）开始调查一起纵火案，这起案件可能与十五年前发生的一起事件有关，那是一起悲剧性的悬案，艾琳初到暴力犯罪科（Violent Crimes Unit）时就曾面临这一挑战。民众因想到有个纵火犯逍遥法外而惶恐不安，艾琳和她团队其他成员所承受的压力巨大……

一具被肢解尸体的一部分被冲上了哥德堡郊区的一个多岩石的海岸。侦探督察艾琳·胡斯唯一有价值的线索是躯干上一个醒目的纹身。她的调查将她引向了哥本哈根，在那里，她陷入了一场对一个堕落而凶残的杀手的追捕。她知道这个杀手很快就会再次作案，而且变得越来越……

A man jumps from a balcony and dies. His terrified wife witnesses the event in a nearby taxi cab. Once Irene Huss arrives on the scene, it soon turns out that what appeared to be a tragic suicide is actually a brutal murder, and the victim is one of Gothenburg's wealthiest men. When it becomes clear that a biker gang is involved, the investigation gets even more complicated and Irene finds herself tracking down a shrewd and dangerous murderer among ex-millionaires, motorcycle gangs, drug-dealers and blackmailers. At the same time, she has to deal with everyday life and a teenage daughter who has decided to join a gang of skinheads with Neo-Nazi tendencies. Written by Svensk Filmindustri

河里惊现一具年轻漂亮女性的尸体，她手上戴着别人的钻石婚戒。伊琳娜及其团队深入调查这起案件，发现该女子并非溺亡，而是头部遭钝器击打致死。此女子从未登上失踪名单，人们虽知道她是谁，但对她的情况却一无所知。

伊琳娜·胡斯回到犯罪现场，着手调查一起年轻男子死亡后被弃尸的案件。经调查发现，该男子在死前遭受了折磨、虐待和性侵犯。胡斯意识到这名男子并非唯一的受害者，而只是第一个。线索引领她和同事来到一家夜总会。此时，胡斯的女儿及其朋友也在现场，她们全然不知危险正在悄然逼近。

港口的海域上漂浮着一辆小汽车，驾驶座上躺着一具头部中枪而亡的尸体。线索让伊琳娜及其团队锁定了一个总挑战法律权威的摩托车帮会。此前处理过一起蓄意炸毁汽车事件后，伊琳娜已明确本案的调查方向。

一名年轻女孩遭莫名袭击后被拖上一辆货车。伊琳娜和她的同事赶到时晚了一步，不过发现了近期一起绑架案的线索。凶手借助网络聊天室诱使目标上钩，他们顺着线索找到了在火车上使用wifi信号的乘客。

一名退休警官在赃车肇事逃逸案件中丧生，肇事车辆事后被发现于一个工业区内被烧毁，车旁还躺着一具年轻女性的尸体。伊琳娜·胡斯和她的同事们着手调查这两名死者之间的关系。为侦破此案，伊琳娜得先找出那名偷车贼，可那名死亡的年轻女孩究竟是谁呢？