Jonna Henningsson can't stand the fact that her ex-boyfriend has gone back to his former girlfriend. In cold blood, she goes to her boyfriend's residence and hits her love rival with a hammer.

In the season premiere, we examine Kjell-Åke Johansson, one of Sweden's worst sadists of all time. Over the course of several months, he tortures a woman on a farm in Aspa outside Örebro so severely that she finally dies. But it's not the first time.

On a summer day in June 2017, Edvin Gyllensvaan tapes an elderly couple to two kitchen chairs and cuts their throats. The previously unpunished father of young children is an enigma to the police.