The Mark Of Abel (Supernatural)

Prestley Mitchell and the Winchester brothers have known each other since they were kids. Growing up as a hunter, Prestley already knew what the whole life had to offer, so she was glad when John decided to take her in. She experienced life with the Winchesters and they grew to be the family she needed.

Many years later, after they put Lucifer back in his cage, their group split, leaving the brothers without their life long friend. Needless to say, they were sad that she wasn't around anymore (Dean the most), but life moved on and the world needed saving once more so the Winchesters were off to save it.

Prestley kept hunting after she left the boys. She hated leaving them, but she had to because of that stupid mark. The Mark had changed her life completely, but she wouldn't change anything she did to get rid of it.

Now, running on a piece of hunter gossip saying that Dean is bearing the Mark Of Cain, she finds her way back into the life of the Winchesters. As their story continues, Prestley tries to help Sam get Dean back to himself, but something seems off to her.

What will happen as they keep trying to get the Mark off of Dean and how will the Winchesters react to finally finding out the real reason Prestley left them in the first place?