Idea gotten from the winchesters heaven and hell by thedoctorisinx
Based on Supernatural from season 5 episode 'changing channels' onward
Bailey Hughes, a eightteen year old hunter gets a big surprise while with Sam and Dean Winchester. The Archangel, Gabriel finds her and tells her she is an angel her self and that he, lucifer, and michael are her brothers. When the Winchesters try to lock lucifer and michael in lucifer's cage, Bailey unintentionally intervenes, closes the cage, and accidentally double crosses Sam and Dean. Bailey starts to uncover more of her past, especially about how she fell with her grace removed, and becomes less and less of her human self. How can she fix everything that she started and not lose everyone she loves.