This is what Tobias and Tris's life would be like if there was no war

It was just supposed to be a normal hunt. There was a Wendigo up in North Dakota. Nothing major. Sam had gone to tackle it himself. He left Dean alone in the bunker for a few days. Suddenly, Cas shows up seriously injured, and Dean gets a call that Sam has gone missing. He can only pick one person to help. Will he stay with Cas, his best friend, or go find his brother?