Winging It

AU based on Supernatural episode 5:04 'The End'. Dean's attempt to kill Lucifer with the legendary Colt pistol goes horribly wrong, but a resurrected Castiel manages to save both their lives with an unorthodox plan B. Can these two share a body, rescue Sam from Lucifer, and save the day without driving one another insane? Destiel. Rated T for the duration.