The Hunt for a Killer

10-year-old Helén Nilsson disappears on Easter 1989 in the small community of Hörby. It's a chilly evening and Helén will meet two classmates at the discount store a few minutes' walk from home, but the young friends never meet. Six days after the disappearance, Helén's wounded body is found, raped and strangled. Detective Commissioner Pelle Åkesson wants to work with the investigation but is abruptly rejected by her boss. When Helen's mother shows up at the police station and asks Pelle to take on the case, he promises to find Helen's killer.

The Helen investigation is on fire and Pelle Åkesson is following the investigation's dwindling existence. Two women are found murdered and night walking groups begin patrolling the streets in Kristianstad. Pelle and his team interrogate suspects and follow up on clues, but power struggles and political games complicate the investigation. Pelle's new colleague Monica Olhed's interrogation methods are starting to be discussed at the police station and a night walker catches Pelle's attention and is taken in for questioning.

The unsolved murder of Helén Nilsson continues to torment Pelle. To move on, he begins to dig into the murder of the prostitute Jannica Ekblad. The investigation leads them to a new suspect, a man called the Pig. Pelle wants to investigate the murders in parallel, but this leads to a conflict with his boss which has major consequences.