When God, or Chuck as he likes to be called, brings home the new baby angel, the archangel Gabriel is overjoyed, Michael, Balthazar, and Raphael are excited, and Lucifer is furious. Being Chuck's favourite, Lucifer thinks that the new angel will replace him. When Lucifer rebels, Gabriel sees that this action is the beginning of, not just the world falling apart, but the whole universe. A few thousand years later, Gabriel leaves Heaven, leaving behind a grief-stricken Castiel, and finds his first vessel. After a couple years, Gabriel runs into Sam and Dean Winchester, two demon hunters determined to rid the world of evil. When Gabriel agrees to side with them, Gabriel knows that he has taken the first step toward his fall.