All of the main storylines of the season will come to a head in the season finale and will be wrapped up in a suprising way, Eric Kripke told TV Line. Eric also gave more details on the effects of Sam's wall coming down.
Question: Got any scoop on Supernatural? —Kim
Ausiello: Series creator Eric Kripke warns that the season is “building to a left hook that I don’t think [fans will] see coming. We will bring all of this mythology to a head. We bring purgatory to a head. We bring the war in Heaven to a head. We bring the mother of all monsters — the wall in Sam’s head — to a head. All of it does come together, but I think in a way that’s really unexpected and surprising and really great.” Speaking of that ticking time bomb in Sam’s noggin, how does Kripke (who penned the finale) plan to resolve that? “You don’t want to blow it off,” he says with a laugh. “You don’t want him to be a drooling vegetable on the floor either because that’s not super-exciting to watch last I checked. But I think it’ll be good. I think it’ll be really powerful and emotional. Hopefully, the fans will enjoy it.”