A young pregnant woman is buried in the sand, slowly being submerged by the tide. 25 years later, the sadistic murder remains unsolved. Olivia Rönning at the Police Academy studies the case as a cold case exercise. Olivia becomes almost obsessed with the murder when she discovers that her father worked on the investigation. She quickly realises that she needs to find the lead investigator, detective Tom Stilton, but he has gone to ground.
Olivia is completely absorbed by the case and goes to Nordkoster to visit the murder scene. When she comes to the beach at Hasslevikarna bay, a man appears with a rolling suitcase. Stilton finds out through Situation Stockholm that Olivia is looking for him but is not interested in making contact. He has other concerns, like his homeless friends being beaten up.
Stilton finds his friend Vera severely beaten and decides to try to find the perpetrators. Olivia has received information that a former escort girl, Jackie Berglund, figured in the inquiry on the beach case and decides to examine her a little closer. She contacts a journalist who interviewed Jackie a few years ago, Eva Carlsén, for advice on how to approach her. Linn Magnuson, CEO of the mining company, receives a malicious call and realises that the call could crush both her and the company.
Olivia continues to look for information about Jackie Berglund, but goes a little too far when she visits Jackie’s store “Odd & Right.” Jackie has already heard that a young woman has been digging around in her past, and she quickly realises that it is Olivia. Olivia’s mother tries to tell Olivia to stop digging around in the beach case. She does not want to see Olivia become as obsessed as her father. Tom Stilton slowly starts to get in shape so that he can pursue those who murdered Vera. He makes contact with his former snitch, Mink, for help in finding them.
Children find a car in the water where they are swimming. Inside the car is a dead man. Stilton’s old colleague and ally, Mette Olsäter, takes the case and quickly starts a murder investigation. The dead man, Nils Wendt, has been missing since 1987. Where has he been all these years, and why has he turned up now? Olivia tries to take it easy after the attack. She is certain that Jackie Berglund is behind it. But she is more worried about her cat, Elvis, who she hasn’t seen since.
Olivia contacts Ove Gardman, the man who witnessed the beach murder as a child. He tells her that he met Nils Wendt in Costa Rica. Olivia gives this information to Mette Olsäter, who decides to send Abbas – a friend to both she and Stilton. She wants to see if he can find anything that can explain Nils Wendt’s murder, and if there is any connection to the murder in Nordkoster. The police manage to get Nils Wendt’s mobile phone working and find that his last call was to Linn Magnusson, who now realises that she must find the original recording of the conversation that could destroy her life.
Abbas finds Nils Wendt’s house in Costa Rica, as well as his friend, Bosques. Bosques tells him that the woman who was murdered on the beach in Nordkoster was Adelita Rivera and that she was in a relationship with Nils Wendt. Abbas also gets a bag of material that Wendt left behind, in case he didn’t return. Mette realises that the investigation of the murder in Nordkoster and Nils Wendt’s murder are now one and the same. Linn Magnusson has sent people to look for the evidence Wendt left in Costa Rica.
Stilton is visited by his ex-wife in the caravan. She wants to see how he is and tell him that she has got a match on the DNA from the hair slide – it is Jackie Berglund’s. Mette immediately calls Jackie in for questioning and wants Stilton to participate. After the interrogation, Jackie sees Olivia waiting outside. This worries Stilton, because he knows that Jackie will stop at nothing to protect herself. Abbas is on his way home from Costa Rica, heading directly to a meeting with Mette, Stilton and Olivia.
Abbas manages to deliver all of the material to Mette and her group. When they listen the recorded phone call between Linn Magnusson and Nils Wendt on the cassette tape, they go straight to Linn Magnusson’s house. But they get there too late. Olivia is frustrated with the beach case, and decides to take revenge on the man who killed her cat. Stilton realises that the police are not going to spend any time on the investigation related to the murder of Vera Larsson and the beating of the homeless. He must take control of it himself.
Mette gathers everyone at the police station, including Stilton and Olivia. The pieces begin to fall into place, now they have identified the person who had the earring and are just waiting for a crucial DNA analysis. They have also identified a new witness who was in Nordkoster. Mette calls in a new suspect for questioning. But how does the murder at Nordkoster fit together with the murder of Nils Wendt? And what is the motive?