When the imprisoned serial killer Lasse Maasalo's face and a text "Let's make the world a better place" are painted to an underpass with blood, Kari Sorjonen is forced to confront the most difficult case of his career.

With the city in crisis, Anneli faces an ultimatum, and Kari must decide just how far he's willing to go to stop his nemesis.

A mysterious outbreak leaves Kari locked down in a hospital ward — just as he and the team brace for the return of Lasse Maasalo.

Shocking news and an unsettling encounter stoke tensions in the community. Kari leaps into action after finding Janina's diary.

The ritualistic murder of a young swimming instructor draws the team to a conservative religious community teeming with secrets.

After another key figure in the case is found dead, Kari revisits a suspicious tragedy in the family's past. Janina interrogates Jarkko on camera.

The week's events play out from a different angle, revealing new dynamics within the family. Meanwhile, Kari grapples with his own father issues.

When a man is murdered inside his room at a retirement home, Kari and team question his three very different sons and his much younger girlfriend.

As the team races to track down potential victims, Kari scours the country for news of the killer's daughter. A disturbing video captures a new crime.

Over Niko's objections, Kari dives into a series of grisly crimes that yield more echoes of past cases. Janina grows frustrated with her father.

As Kari and family wrestle with devastating news, Heikkinen calls to ask for help with a kidnapping case, and Katia stands trial for attempted murder.