Supernatural hasn't spent a lot of time on relationship stories, and this is a really nice mechanism to do that without imposing that on the forward ….

Dean [Winchester] is piling on Sam [Winchester], somewhat, for this. What happens is that these brothers start to discover more about what they've do….

Closing the gate is meant to be a season-long arc, but the questions that come up in the quest, and the series of reveals and discoveries, are meant ….