If by some chance you’ve never read Mamishka’s Fallen, well…now you have something to do with your empty evening.
It starts out with John as an angel, and Sherlock a mage, and then they promptly fuck things up. The amount of research and detail she puts into this story (and its WIP sequel, Invisible Bonds) is absolutely flabbergasting. She pulls in folklore and the occult and various religions in a way that makes you truly feel them as a part of the fabric of this world, and John and Sherlock are both sharp and broken and complicated, and pretty much this story just makes life beautiful.
BBC Sherlock rec: Fallen by mamishka