Anyone actually catch on to this show yet. Its currently running season 4.
Here is what google say its all about
When Portland, Ore., homicide detective Nick Burkhardt receives a visit from his sick aunt, he gets an explanation for some strange events in his life. She informs him that he is descended from a long ancestry of "Grimms," not just chroniclers of fairy tales but hunters charged with protecting humanity from supernatural creatures. Soon Nick discovers that he can see the creatures, "wesen," who look merely human to most people, and he must bear the responsibility of his ancestors and deal with the mythology of the Brothers Grimm. As Burkhardt tries to cope with the newfound dangers of his life without alarming his fiancee and his partner, he becomes more knowledgeable about the ancient rivalry -- with help from a peaceable clockmaker.