Heaven or Hell? It's All Irrelevant Now

Heaven is bland and depressing, when people are missing. Dean dies and goes to heaven, reunites with Charlie, who wants to save Cas even though he knows it isn't possible... She recruits Ash, who in turn recruits Jo, together they convince Dean to come with them. Sending them on the journey of a life time through the afterlives, interacting with past faces... Better than it sounds.