A person phoned the office today; his name was Dean Henrickson.
This immediately triggers an AU plot-bunny wherein John's business partner Mike succeeded in having the boys removed from John's custody right at the start, (after which John went off the deep end a little more than he did in canon and as a result of not having the grounding influence of the boys is way darker and more reckless, but still around hunting). Victor Henrickson's folks adopted Dean and Sam and they were all raised together.
Sam is a really normal kid starting to think about careers and Victor has gone into law enforcement or a criminology degree, but Dean never forgot John and the fire and can't settle in as the middle child of the Henrickson family. John never stopped looking for the boys, (or maybe secretly checks on them every so often but is determined to keep out of their lives so they'll get a chance to have normality).
In the summer before his senior year at high school, Dean runs off to find John. Victor (as Dean's big brother and a very junior or trainee FBI agent) takes leave to try and bring him home and Sam will not stay behind and goes along with Victor. All the while YED and his minions are tracking Sammy, and Victor and Sammy are tracking Dean, and Dean's tracking John, and John's tracking YED and keeping watch over the boys from afar...
...and unfortunately, I'm not writing it. It will likely never go farther than this summary. I can't do it justice and I'm being eaten alive by other plot-bunnies with higher priority and I just don't have the time. :-/
Who knows, maybe someone else will adopt it. *herds into the far, far corner of the bunny corral*