It's a case that dead-ends at a magical door. But this Open Sesame can only be triggered by married men or women. Mary steps up to bat and reads the words, but the magic is finnicky. It only works for current marriages.
CAS: "The definition of marriage is broad: political, conciliatory, locational, common law..."
(*in the background, Dean is lobster-red, thinking his inclusion of common law means them ofc*)
As the door slides open, Sam crows in victory, and they continue on.
SAM: "Hey so what opened the door? You got a wife we don't know about?"
CAS: "Yes. I suppose I owe a great deal to the djinn queen."
DEAN, face falling: wHaT?????