Veronika and Mirek are going through a difficult time in their relationship, and he decides to treat her to an unusual experience: a horror-themed tour for Valentine's Day, following the trail of mysterious crimes. The destination is the Slavkov Forest, nicknamed "the knot of evil." Other characters join them on the journey: Alex, the nervous guide; Ludmila, a mystery novel enthusiast; Honza, an extroverted influencer looking for a scoop; and the couple Dana and David, who represent a potential warning to Veronika and Mirek. With each stop on the tour, however, something begins to change. When Veronika discovers a strange doll and sinister voices echo through the woods, plausibility gives way to the paranormal: the legend of Navka, a spirit from Slavic mythology, seems to come to life. The journey turns into a nightmare from which there seems to be no escape.