A customs officer is found dead at his home and the police initially believe that he has taken his own life, but when a connection to a murder in Marseilles is discovered, Olivia Rönning and Tom Stilton are once again drawn into a complex murder mystery.
Mette and the police now suspect that the assassination of Bengt Sahlman is linked to a batch of drugs stolen from the Customs Office. Meanwhile, Tom accompanies his friend Abbas to Marseille to help him find out what happened to Samira – a risky move because a gang has put a price on Abbas’ head…
Despite opposition from Mette, Olivia continues to investigate Bengt Sahlman’s death. She meets the mysterious Alexander Popovic again and their conversation arouses interest from powerful forces in the business world. The search for the truth behind Samira’s death in Marseille continues, but in ways that Stilton isn’t comfortable with.
Abbas is hovering between life and death and Michelle can no longer guarantee Stilton’s safety so forces him to leave Marseille. New information makes Mette ponder over Stilton and Abbas’ trip to Marseille, but someone new enters the investigation that makes things very difficult for both Mette and Stilton.
Matte’s suffers heart problems and is admitted to hospital. This may be just what Rune Fors needs to remove her from the investigation, but Stilton does everything in his power to stop him. The raid on Klas Hall provides Mette’s colleagues with an interesting lead. Olivia goes undercover to access Borell.
Mette is now on sick leave, but still tries to keep up to date with the case and makes plans with Tom. Abbas is determined to find Samira’s killer, but while he is in hospital time is running out and the French police have a head start. Meanwhile, Olivia tries to convince the Swedish police to look for Sandra’s missing computer at Borell’s place.
Olivia is determined to retrieve Sandra’s computer from Borell’s house. The house is heavily guarded so it could be a dangerous mission, but a couple of drawings of the building should swing the pendulum in her favour, and being on her own will not stop Olivia in her quest for the truth.
Tom’s nemesis Rune Fors finally gets the chance to ensnare him, but the last piece of the puzzle is missing and Mette doubts that he has the right person. Olivia makes a breakthrough in the investigation thanks to Sandra’s computer and continues working with Alex to bust Borell and his cronies.
Mette and her team get closer to solving the case, but the police aren’t the only ones closing in. Journalist Popovic makes a breakthrough and now it seems that everything is connected, but who murdered Bengt Sahlman? At home in Stockholm, Stilton makes both an unexpected and unwanted visit to Luna’s boat.
The French police arrive in Stockholm to question Bressant about the murder of Samira. The end is in sight, but it is still not clear who murdered Bengt Sahlman. Are Mette and her team on the right track and will they solve the mystery once and for all?