Dean is an Angel. Castiel is a Vampire. Castiel has been feeding off of human blood all his life and the Angels thought that the killings were just animal attacks. But one day, Castiel feed on too many humans and the Angels started getting curious. Usually only 3 or 4 humans would die a day, but now, 12 humans were dying. So, Dean was sent down to Earth to try and find out who was killing the humans. His mission was that once he found the one who was the killer, he would kill that someone. Keep reading to find out what happens when Dean and Castiel meet for the first time.