I can't remember to much about this story, so sorry in advance.

I don't think Sam and Dean are a couple at the beginning of the story and this might be after Dean comes back from Purgatory, I think Sam is feeling guilty for Gabriel's death and somehow Kali gets involved either with helping Sam find a spell to bring back Gabriel or going to Sam to make a deal to bring Gabriel back, maybe that she can bring Dean back if Sam brings back Gabriel. I believe by the end Sam and Dean become lovers.

Im sorry I really can't remember much, the only parts that stick out is Kali, Gabriel coming back (I think he possesses Sam for a little while) and Sam and Dean are lovers by the end.

Help please???