Gray Sky

Natasha Gray didn't have the best childhood. Her parents were killed by malevolent witches and then her aunt trained her to be a hunter, a killer of monsters and demons. After her aunt dies of a heart attack, Natasha is left on her own at the age of nineteen. Then her luck changes and she meets Bobby Singer, a fellow hunter. He introduces her to her soon-to-be family, Sam and Dean Winchester. Her life turns into a rollercoaster of action and adventure, the Winchester's along for the ride.
(I don't own any of the characters/ideas except for Natasha and her plot line)