Detroit, Blood and the Apocalypse

           Soon the brothers are off going to hunt down the four horsemen and cut off there ring fingers to retrieve the "keys". When going after famine, Sam starts to desire demon blood again. The blood of a demon gives Sam special powers, and he is the only one who can have what he craves and become stronger from it. Lucifer and the horsemen want Sam to get hooked on it again, so he will be ready to be the vessel of Lucifer to start the apocalypse. Lucifer cannot stay in his current vessel because Sam is his true vessel and all other vessels with deteriorate.
          Finally coming to the conclusion that the apocalypse is inevitable, Sam agrees to be Lucifer's vessel. The brothers, along with the help of Castiel and Bobby, go looking for the devil. They track him using Omen's they find in the news. This leads them to Detroit. In almost every encounter with the devil his reminds the brothers that everything will end in Detroit, and he is right. Before Sam can say yes he has to drink a lot of gallons of blood, to allow Lucifer to stay inside and not explode, (kind of ironic).

          After Sam says yes to the Devil, he tries to control him and force him into the cage. However, Lucifer is too powerful and goes off waiting for the final battle with Michael that starts in a field.
          Dean decides that he should be there, because Sam is still in his body with Lucifer, so he wants to help him find some control. After Sam pulls the two angels into the pit, Dean agrees to his promise and goes off to find Lisa, his only true love, and her son Ben. He lives with them for a year and starts a family with them, supernatural free, after he stopped the apocalypse.