5.22 - Swan Song

Going with Dean to Lucifer's place, Sam--expecting to lure the cunning being and trap him with the Four Horsemen's ring--agrees to be His vessel. However, Lucifer is smarter and uses his son's vessel instead to fight against Michael, who is using Adam's vessel. Dean and Chuck discover the place of the final battle--an old cemetery in Lawrence--and Dean heads there in his Impala with Bobby and Castiel. Will they be able to avoid the inevitable?

Source: IMdb