瑞典某市E6区发生运钞车劫案，劫匪穷凶极恶，组织严密，其背后俨然有一个庞大的恐怖犯罪组织暗中操纵。为了追查运钞车的下落，对抗无法无天的犯罪组织，国际警察机构命令特别调查组GSI追查此事，连阔别警队15年之久约翰·福尔克（雅克布·艾克伦德 Jakob Eklund 饰）也回归部队。他们将目标锁定在埃里克·达沃达（派勒·博兰德尔 Pelle Bolander 饰）等臭名昭著的犯罪头目身上，跟踪调查与他们有关的蛛丝马迹。 　　而在这一过程中，城中的劫案愈演愈烈，犯罪分子们似乎与GSI展开了一场充满枪声血光的竞赛。精英云集的GSI面临巨大的挑战，残酷的正面对抗在所难免……

约翰·福尔克在哥德堡警察特种部队GSI执行例行任务。在一名挪威卧底警察和一名哥德堡最重犯罪团伙的平民渗透者的帮助下，GSI正试图购买六支突击步枪，从而将其从街上赶走。但突然间，当一个新的未知玩家突然立即想要购买不仅是这些武器，还有更多的武器，包括穿甲弹时，一切都发生了变化。GSI意识到这不可能是任何普通的强盗。有人会在哥德堡街头发动战争。与此同时，约翰·福尔克的渗透者弗兰克·瓦格纳的情况变得越来越复杂，他渗透的团伙头目意识到自己的一个人向警方泄露了信息。

弗兰克·瓦格纳深入卧底，渗透到欧洲最危险的黑手党——俄罗斯东部，由前克格勃官员组成。

　　在学校附近的停车场，一个陷车器爆炸了。约翰·福尔克正在追踪一个他过去认识的人，这个人因谋杀罪在监狱服刑8年。

约翰·福尔克和他在GSI的同事们追捕从东方引进年轻女性并强迫她们卖淫的性贩子。

约翰是一名双手紧握的哥德堡警察，他发现自己与珠宝劫匪发生了枪战。烟雾散去后，一名被同伙枪杀的劫匪和一名无辜的旁观者死亡。包括海伦在内的三名目击者确认，这位非凡的暴徒利奥·高特是这位死去的骗子喜欢开枪的同事。高特很快威胁到三名目击者，只有佩戴徽章的英雄约翰才能救他们。

约翰·福尔克和弗兰克·瓦格纳终止合作，弗兰克开始与警方秘密合作已经两年了。弗兰克对凯文的搜寻跨越了约翰的调查，开启了他们之间的新合作——最大的不同是，这次是弗兰克的个人事务。

It's a beautiful day in Slottsskogen, Gothenburg idyllic city park, when suddenly the unthinkable happens - gunfire amidst all people. Two gangsters shooting game against each other and a large police operation starts. The conflict grows rapidly to involve several gangs from Gothenburg underworld. GSI switched to try to identify a new thread which proves to be both larger and better armed than any other. The only clue is a tattoo on one of the killed gang members.

GSI second in command, Sophie Nordh, flips gangster leader Seth Rydell and convinces him to infiltrate a rogue military group. For the first time GSI Chief Patrick Agrell realizes that he is using a ruthless psychopath as an infiltrator. Can Seth be trusted or does he have his own agenda?

Johan Falk's stepdaughter Nina has gotten in contact with her biological father, Orjan, discovering that he is in debt to an Estonian construction company in Gothenburg, leading to Nina's kidnapping.

一群专门抢劫购物中心保安的年轻劫匪正在哥德堡肆虐。一名无辜的路人被杀，抢劫案出错。该团伙的年轻头目瑞奇试图迅速找到一位专家，他可以清理爆炸的染料包中的钱，而约翰·福尔克和他在GSI的同事们则加快了他们的搜寻。

　瑞典某市国王路公寓发生一起入室凶案，弗兰克•瓦格纳出于自卫错手杀死持枪入室的歹徒，瞬间被推向舆论的风口浪尖。他带着妻儿找到了GSI的特警约翰•福尔克寻求帮助。与此同时犯罪团伙头目推测弗兰克可能是潜伏在圈子里的卧底，找到平素与弗兰克有贸易合作的商人赛斯，恐吓其散布消息重金悬赏捉拿弗兰克的人。紧接着一名GSI女警员无故被枪击致使昏迷，更令案件陷入重重谜团。警察当局威胁弗兰克接受不平等契约，不然便要令他成为全国通缉犯。弗兰克愤怒出逃。随着五年前一宗击毙犯罪分子的案件重新被想起，真相渐渐浮出水面，人们口中的杀人嫌犯弗兰克原来真是为警察当局兢兢业业的卧底，也就是传说中的“代号丽莎”，可他终究难逃亡命生涯……

Falk is blackmailed into smuggling a truckload of guns from Latvia.

When Johan and his colleagues are watching Seth and his gang member Jack, they stumble on a larger case than they expected. Seth is selling arms to terrorists, but without Jack's knowledge, in a car where Johan's old colleague Pernilla mysterious appears. While Johan begin researching what Pernilla and SÄPO is doing, Jack suspects that everything is not right with Seth and that he's working with the police.

　　约翰福克在海牙欧洲刑警组织工作五年后，回到哥德堡加入瑞典警方精英部门GSI特别行动小组，打击各种犯罪组织。 他成为一名卧底线人的接头人，在北欧地区打击罪犯、军火商、贩毒者和卖淫团伙…

The police station is locked down. A snitch is compromised. Drastic and unexpected events take place. Both inside and outside the police station.

The unknown, large mafia organization is now showing its true face. The pressure that GSI and John Falk and his family have put on the organization, makes them fight back on all fronts. The rule book is thrown out. But to go after Johan Falk's family and trying to kill his wife could be the biggest mistake the organization has ever made. GSI closes up around Johan's family and the final battle begins ...

After the book became a success, the creator confirmed that there will be a movie out of it.