On Supernatural Season 9 Episode 17, Sam and Dean wi have a Crowley problem.
He's hooked on human blood and has forgotten about his mission to find The First Blade!
The Winchesters first mission is to get Crowley off the juice (which could fill an entire hour with all of the entertainment possibilities) and then to find The First Blade so they can think about their other problem:
Ridding hell of Abaddon.
It turns out having an ally in hell is probably better than having an Abaddon down there, so descending Crowley back onto the throne might look pretty good.