Castiel sends Dean back to 1973 where he meets his parents who are just about to get engaged. He is told to stop something. He finds out that mom Mary was actually a hunter growing up. He tells her that he is a fellow hunter and is introduced to his grandfather Samuel and grandmother Deanna, both of whom are hunters. Samuel is working a demonic signs case but doesn’t trust fellow hunters.
Dean gets himself involved in Samuel’s case and learns that is involves the yellow-eyed demon. Dean tells him that he knows what to do on this case (he knows where the colt is and uses dad’s journal to learn where the next deal will take place) but Samuel hasn’t even heard of a yellow-eyed demon.
Mary knows that John is about to propose. John isn’t a hunter and Mary wants to get out of hunting as well since she hates it. She would hate for her kids to be raised in the lifestyle. Dean tells her that even though it sounds crazy, she shouldn’t get out of bed on November 2, 1983 (the day yellow eyes killed her). Castiel tells Dean that if he succeeds, his family won’t become hunters and those his family saved will die. Dean doesn’t care, he just wants to save his parents.
The next person to make a deal happens to be one of Mary’s friends. Samuel and her go to help out and Dean eventually gets there as well with the colt. He misses and now believes this is where yellow eyes began to eye Mary up for a deal. Dean tells Samuel that he is his grandson and he believes him. However, Samuel isn’t himself anymore, yellow eyes has took his body. Yellow eyes knocks Dean down and tells him his plan is just to pick the perfect parents to foster his children. Mary is one of them. Yellow eyes stabs his body to kill Samuel then takes down Deanna as well before escaping.
John tries to propose to Mary but yellow eyes gets to her. He snaps John’s neck and tells Mary she’s an orphan now. He offers to bring back John. Mary is obviously cautious when it comes to a deal but he tells her that as long as he isn’t interrupted, nobody will get hurt. She takes the deal as Dean arrives. Yellow eyes escapes and John comes back to life.
Castiel transports Dean back to the present. Dean knows he didn’t stop anything but Castiel tells him destiny can’t be changed. He just sent Dean back so he could see what truly happened. He also tells Dean that Sam is headed down a dangerous path. Dean needs to stop him or they will do it.
