Tipped off by the killer's horrific photofit, the investigators unearth the Krampus legend – a symbolic creature infamous for punishing the naughty and unworthy. This leads them to Sebastian Brunner, head of a rural sect, whose books on the end of civilisation seem to have inspired the killer. Through the cult leader, Ellie and Gedeon manage to contact the perpetrator via the internet. This achievement, however, can't stop the murder of a YouTube starlet on a lake near Salzburg.

The demanding investigation has affected Ellie in a major way. The German policewoman and the Austrian cop bicker and fight constantly. While her positive life views get dulled and stunted, Gedeon's initial indifference changes into an obsession for cracking the case. After one lead brings them to yet another dead end, they have to start again from the top. They dive into case files of unsolved murders over the past years, hoping to find any trace of the serial killer.