In the 1950s, Hellboy is enlisted to aid rookie paranormal researcher, Bobbie Jo Song, in the transportation of a deadly creature. However, their mission soon goes awry when an accident leaves them stranded in the forests of rural Appalachia, where a small community resides, haunted by demonic forces. With all clues pointing towards witchcraft as the culprit, Hellboy and his allies must hunt down the source of this evil - a being known as 'The Crooked Man' who has been sent to Earth to harvest souls for the devil.