A gruesomely staged body is found on the Austro-German border. Police Inspector Gedeon Winter from Austria and Commissioner Ellie Stocker from Germany join the case and suspect this murder is merely the beginning of a larger scheme.

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.

In Salzburg, a fashion mall becomes a war zone after a deadly bombing which strikes fear in the general public. Politicians and the media demand immediate results from the police; the Krampus Killer makes it personal when he goes after Ellie.

A man wearing a Krampus mask is shot during a gunfight with the police and it appears as though he is the sought-after Krampus Killer. However, Gedeon suspects this is merely a copycat, a theory which the politicians and the press refuse to believe.

In the Austrian region Steiermark, a decomposed female body is found buried in a box. Gedeon senses the Krampus Killer has struck again and he convinces Ellie to start an unofficial investigation with him. They discover new facts about the victim.