As a deadly crime spree begins to surface, a century-old urban legend takes shape in Portland's sewers and becomes Nick's latest case. In Europe, Adalind meets Prince Viktor, who’s come to bring those responsible for his cousin Eric’s demise to justice. Meanwhile, Captain Renard responds to the recent attempt on his life.

After a string of delinquent teens go missing, an old Wesen tale of an evil Santa who brings more than just a lump of coal may be the prime suspect. The investigation intensifies as Nick and Hank take things a little too far. Meanwhile, Monroe enlists Juliet to surprise Rosalee for their first Christmas together with unintended results. Elsewhere, Captain Renard’s tour of Europe brings him closer to tracking down Adalind.

Nick and Hank investigate a cop killer who scalps his victims. Meanwhile, Juliette begins to communicate with Nick's mom via email and Adalind finds herself much closer to delivering her baby than she previously thought. Elsewhere, Monroe's parents decide to surprise him and Rosalee with an early arrival to Portland after learning some exciting news.