The 'Other' Winchester (A Supernatural/Avengers Love Story Crossover)

Allison Stark is the adopted sister of Tony Stark. Neither of them ever knew that she was adopted until after their parents died. She only has one item on her from her blood family, two rings on a leather strap. They were meant for her brothers but her father gave them to her so her older brother and him would recognize her. Her whole young life she was into the supernatural, this caused her 'father' to be very wary on certain subjects. Three weeks before the battle of New York two strange men walk into the city. They claim to be FBI but Allison knows better. She was raised as a Stark, she notices things. They are investigating weird deaths around the city. Being apart of S.H.I.E.L.D and being a Stark plus the possibility of being an Avenger has her at every scene. Which causes the Winchester brothers to suspect the her as well as be wary of her.