Homicide detective Nick Burkhardt has been at the center of some very gnarly investigations, and he thought he'd seen everything. When he begins having visions of the people around him as twisted creatures from dark stories. A visit from his aunt provides him with a surprising family lesson - he is a descendant of those who wrote the fairy tales and those gifted with seeing the creatures within them as they really are. It is his responsibility as a Grimm to keep the balance between the average humans and the beings he once believed were only found in the pages of books.