Twelve Days of Krampus

Opening quote: "O Christmas Tree, O Christmas Tree, How steadfast are your branches!"

During Christmas time, two teenagers named Derrick Bryce (Shane Coffey) and Quinn Baxter (Alex Mentzel) steal presents from a car. Suddenly, a person dressed as Santa calls them "naughty", revealing itself to be a horned creature and attacks Derrick while taking Quinn.

In Austria, Tavitian (Bernhard Forcher) kills Verrat members that seem to follow him. He arrives at a Resistance to meet with Renard (Sasha Roiz), Meisner (Damien Puckler), and Sebastien (Christian Lagadec). However, the members of the Resistance have doubts about Renard for his blood although he manages to convince them by telling them he has a Grimm.

Nick (David Giuntoli), Hank (Russell Hornsby) and Wu (Reggie Lee) inspect the body of Derrick but Wu freaks when he finds that he is not dead and the attacker left a piece of coal. Meanwhile, Monroe (Silas Weir Mitchell) calls Juliette (Bitsie Tulloch) to help in redecorating the house, as a surprise for Rosalee (Bree Turner), as they are having their first Christmas together. During a visit to Derrick in the hospital, he gets freaked after he sees a Santa in the hallway.

Another teen steals a woman's presents and while checking on them, is attacked and subdued by the same horned Santa. A man watches the event but the creature does not attack him and again leaves a piece of coal. In Vienna, Renard and Meisner sneak in Adalind's hotel room and find her substance in the jar and leave a rose and a note for her, warning her to meet with him in a cafe and to watch out from the cameras. Monroe shows Rosalee the decorations in their house but Rosalee reveals that she does not like Christmas very much after her uncle and aunt died on a car accident on Christmas's Eve, hurting Monroe. The next morning, she wakes up to find that Monroe took away all the decorations.

While looking for the Santa responsible, Nick and Hank interrogate a Santa in the mall who turns out to be a Schakal. He panics when he finds that Nick is a Grimm and runs. Nick goes after him and tackles him while people film the event, reaching news reports. Nick and Hank asks Monroe about it and Monroe quickly deduces that the creature is Krampus. Krampus is a creature that takes the "naughty" people and subdues them to take them to a forest and then hangs them from the tallest tree as punishment for their actions. He also adds that when the Winter Solstice arrives, he will devour those children. To make matters worse, they're exactly on the Winter Solstice.

While discussing where is the tree, Bud (Danny Bruno), while denying Krampus' existence, deduces that the tree may be in Council Crest Park. They go to the forest and find the people in the tree but Krampus (Derek Mears) arrives and attacks Nick. Although he is stronger than Nick, Nick manages to knock him out. They debate what to do with him as the police won't have evidence linking him to the kidnappings and he could disappear for another year. To their surprise, they find that Krampus woges into a human form (Darius Pierce).

In the precinct, the human Krampus explains that he has his memory erased every Christmas and the day after the Winter Solstice, he wakes up with a Santa suit. To Nick's surprise, the human Krampus does not have knowledge of the Wesen world. Finding no other choice, Nick decides to inform the Wesen Council to handle the situation. Monroe returns to his house to find Rosalee asleep in the couch and finding beer and cigars instead of cookies and milk (this was the tradition her aunt made every Christmas), causing him to smile as he finds that she has finally celebrated Christmas.