Yellow eyes did not just kill Mary. He also took Sam. He took all the children. Although most of not all but Sammy died along the way do to brutal training and conditions. Sam was raised tough by demons and on demon blood. When he is 14 John and Dean find him and get him back. How will they deal with a traumatized child, whose highly addicted to demon blood, dangerous who does not know what it means to be a part of a family. I would prefer this story to be a good and protective John and Dean story.