Dean and Castiel went back to Purgatory to find the one thing that can kill Chuck a Leviathan Blossom where a old enemy Eve was out for blood. Sam saw the future while trapped with Eileen by Chuck where he lost hope. Chuck is the real snake of Eden tempting Sam and sowing dissent between him and Eillen. Dean finally admits he was wrong and apologizes (sort of) to Castiel. Sam and Dean are Chucks' favorite show and we've been watching alternative endings! But no matter what Chuck does he can never shake the brother bond between Sam & Dean.