After a tragic car accident, Fredrika Bergman begins working as a civil investigator for the police, but her presence is not welcome. Meanwhile, a girl is taken from her mother at Stockholm Central Station and suspicions are soon directed towards the girl's dad.
Tragedy strikes, another child goes missing and Fredrika, Alex and the others have a race against time to find the serial offender before any more children are harmed.
A priest and his wife, who work with refugees, are murdered in their home and a series of robberies is linked to the murders, but how and why? Meanwhile, Alex's marriage is in trouble.
The police initially believe that the murder of the couple is linked to a criminal organisation and the murder of refugees. A discovery reveals a trail of greed and betrayal that has torn apart families and lives.
When two Jewish boys are abducted on their way to practice, their parents argue about where the blame really lies. Fredrika is seven months pregnant, but her happiness is blighted by the new case.
An Israeli legend tells of the Paper Boy who comes alive at night and takes his victims. What initially appears to be a racist hate crime seems like it could be connected to this myth. He is alive again and wants revenge.
A female student who has been missing for two years is found buried at the Slussen building. It's an old investigation and Alex is personally affected by the case. Further discoveries at the crime scene reveal secrets that are decades old.
Fredrika's private life is dragged into the investigation when Spencer is implicated. Meanwhile, Peder's brother sees more than he should and takes off, and developments in the case prove fatal.
A man who got off a murder charge is found dead in his own home. Before long, another person who seemed to have evaded justice is killed, while Fredrika's private world suddenly collapses.
Peder tries to get back on the investigation team as the body count mounts but he is not accepted any more. A dangerous killer is at large: could an insider be involved?