So, once upon a time I've read this fic, where Michael went missing just before the apocalypse. So they sent Castiel to find him, and make him remember his archangel past. Obviously Destiel happens. Then there is some bad guys issue, and Dean remebers being Michael, which distresses Castiel a lot. But Michael is like cool with everything and cancels the Apocalypse. Then at the end there is a scene were Sam, Dean, Castiel and Gabriel are stitting at the table in the bar/restaurant. And yes, Michael's fall was Gabriel's fault.

I swear to go that I read this fic on ao3. But I just can't find it. I would be grateful if someone knew which fic I am talking about.