The Demons in my head

Nikki Evans saw her brother disappear the night of his tenth birthday. All alone at the age of 15 she set out to find the demon she knew took him away. 3 years later she disappeared and has not been heard from by any one since. Sam Winchester and his brother Dean are hunters. They just don't hunt what you'd expect. They agree to find the siblings and take out the kidnapper. But what happens when they find Nikki and not the brother? Sam and Nikki's life depend on the other, but a string can only be snapped so many times before it breaks... (/Most characters are made up from my imagination, apart from the ones that actually appear in the show. I do make up some scenes quite often but I do not take credit for the ones by the creators of 'Supernatural'/)