The halves of two bodies, one belonging to a female Swedish politician, are disvered in the middle of the Øresund Bridge, which nnects Copenhagen in Denmark with Malmö in Sweden. The body, cut in half at the waist, has been placed precisely on the border between the untries, thus falling under the jurisdiction of both the Danish and Swedish police agencies. After further examination, it turns out that the body is that of two separate rpses, with one half belonging to a Danish stitute. Saga Norén, from the Swedish side, and Min Rohde, from the Danish, lead the investigation to catch the murderer.[4][5]
　　The investigation quickly escalates as a journalist, Daniel Ferbé, whose car was used in the crime, begins receiving phone calls. The caller, who bees known as the "Truth Terrorist", claims to be mitting his crimes in order to draw attention to various social blems. A social worker, Stefan Lindberg, whose sister bees a victim of the Truth Terrorist, bees an early suspect. However, events soon lead the Danish and Swedish teams to nclude that the killer has nnections to the police. They disver that the crimes have been planned over a period of several years. The trail eventually leads them to Jens, a Danish policeman and former close friend of Min's, who was thought to have mitted suicide after an aident on the bridge caused the deaths of his wife and son.
　　In the urse of the investigation, Min and Saga develop a close working relationship, although they are very different people. Min has a twenty-year old son from his first marriage, August, who is now living with Min and his current wife, Mette, by whom Min has three children; after Min has had a vasectomy, Mette disvers that she is expecting twins. Saga lives alone and does not seem to feel she needs a serious relationship, instead picking up men in bars for casual sex. She appears to have symptoms nsistent with Asperger syndrome, resulting in difflty establishing relationships and feelings of inadequacy in managing people; she refuses a motion for this latter reason.
　　After the killer has murdered several people and suessfully thrown red herrings in the way of the investigation, his true purpose - to strike at Min himself - eventually bees clear. Jens, now calling himself Sebastian Sandstrod, first apaches Mette, who is susceptible to his advances, after learning that Min has slept with Charlotte Söringer, a woman who is peripherally involved in the investigation. Sebastian lures Mette and her children to a remote spot where he subjects them to a terrifying ordeal, locking them in with a room and giving her a hand grenade with its pin removed to hold as long as she can. However, Saga realises that August is the real target. The investigation culminates in a nfrontation on the bridge, where she cannot help but tell Min what happened to August and has to fire at him in order to prevent him destroying his career by killing Sebastian, the killer's final intention.