Summary: The homicide of a caged medical researcher forces Karppi, who is on leave, back to work as Nurmi's partner. Incisions on the back of the body lead to a complex murder mystery. Karppi's daughter, Henna, experiences the bleak daily life of a criminal released from prison.

Summary: More victims turn up and the murders seem to revolve around the pharmaceutical industry. Karppi receives a mysterious phone call from Germany regarding the death of her husband. Nurmi is confronted by Laura, who is in deep trouble and has claimed Nurmi as the father of her child. Henna gives her little finger to the devil.

Summary: The remains of bodies are found in the sewer, which Karppi tries to link to the murder mystery she is investigating. Laura is hospitalised and Nurmi starts tracking down the missing boy, Leo. Henna is under pressure from both criminals and the police.

Summary: Laura is target of an assassination attempt and the pharmaceutical company's executives become entwined in the case. Karppi and Nurmi find their way to the hiding place used by the murderer and find a clue to the symbol seen on the bodies. The dual role takes Henna deeper into the underworld.

Summary: The mystery of the symbol leads Karppi and Nurmi to investigate the overdose death of a young girl a year ago. Henna is caught and gets thrown from the frying pan into the fire. Nurmi gets hold of a dashcam video shot in Germany, which shows the surprising circumstances surrounding Karppi's husband's hit-and-run.

Summary: Wanted by the police, Karppi continues the investigation on her own and meets the masked killer. At the mercy of the criminals, Henna is forced to look death in the eye. Nurmi helps Karppi to free herself from suspicion.

Summary: Karppi learns new information about her husband's past. A murder investigation leads Karppi and Nurmi to the trail of a family that has been through a lot. At the same time, the mystery surrounding the pharmaceutical company begins to unravel. Karppi realises that Nurmi is also in the murderer's sights.

Summary: Karppi and Nurmi track the suspect to the ruins of an old monastery, but the murderer strikes first, forcing Karppi to commit desperate acts. The final truth about Karppi's husband's death is also revealed.