Once you've crossed the line there's no going back
When a body is found on the bridge between Denmark and Sweden, right on the border, Danish inspector Martin Rohde and Swedish Saga Norén have to share jurisdiction and work together to find the killer.
The head of the Danish migration agency is murdered brutally, and the murder is linked to a controversial expulsion case. Investigator Henrik Sabroe needs help from his colleague and friend Saga Norén, but she is in prison for the murder of her mother.
Henrik's two main clues in the investigation are the left-wing radical group Red October and the refugee Taariq, who has gone underground. On a personal level he tries to realize that he will never figure out what happened to his missing daughters, but then someone begins to show interest in the mystery.
Henrik and Saga suspect that Taariq and the missing expert on left-wing radicals are hiding something, and collaborate to reveal them. They disagree on how to handle the homeless girls who still refuse to give up their identity.
Taariq recognizes a car related to the case. He wants to push the owner for money, but is himself accused of robbery. Saga fears that will be more murders and Henrik's efforts for the homeless girls end up in disappointment.
Saga and Henrik keep searching for a link between the murder victims. Lillian is reprimanded by her superiors. Dan finds out where his ex-wife and son are and causes trouble. The relationship between Saga and Henrik is tested to the limit and may have hit its breaking point.
Henrik believes he found the connection between all victims and an unexpected finding ends up on the investigation board. At the same time, the crack between him and Saga is greater than ever.
The inquiry into Tommy continues and Solveig still refuses to cooperate. She talks neither with Saga nor Jonas. The question is how long they can keep her in holding if they do not obtain any evidence. Lillian is still under pressure from the management to find the culprit, and now it seems that there is a leak in the department. In the meantime Saga makes a breakthrough in the search for Henrik's family.
Henrik and Astrid are trying to get used to being father and daughter again. Meanwhile Saga gets a breakthrough and the murderer is revealed and arrested under dramatic circumstances. The murderer even confesses to the six killings/revenges. But Saga discovers something which doesn't fit. She goes back to the prison in Sweden and talks to the girl who almost killed her, and here she gets a terrible suspicion: there is another killer - and there is still one person left to be a victim!
