A German entrepreneur has been killed in Austria; evidence links this case to the first murder. Ellie and her Austrian counterpart Gedeon realise they are dealing with a highly intelligent and cold-blooded killer, who sees his victims as symbols.
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 civilization seem to have inspired the killer.
Ellie and Gedeon team up with cultist Brunner to set a trap for the killer. But, they have to overstep legal boundaries in order to get this plan to work. They fake a copycat murder, hoping their target would be lured into reaching out to Brunner.
The investigation takes its toll on Ellie and Gedeon, after they hit one dead end after another. However, when they dive into the case files of unsolved murders, they discover the Krampus Killer’s connection to a strange slaying in Vienna.