First of all, this is a SuperWhoLock fanfiction. Second of all, this becomes a Destiel fanfiction. Third of all, the title is a work in progress!! I would love if anyone has any suggestions, but this title is much better than the previous one.
Sam and Dean Winchester get a case in London, England, but something seems off. the creature that killed the victims is something they have never experienced or even believe in. Sherlock Holmes doesn't believe in any of the supernatural, and this id something that even perplexes the Doctor. They all join forces to get rid of this creature, each of them learning something along the was, and in the case of Dean Winchester, who he loves.
Cas, Dean, and Sam have been hunting together and splitting off to take smaller jobs. The story starts with the three of them on three separate hunts. Cas is human and wounded. He shows up at Dean's motel in need of help. What proceeds is the two of them meeting up with Sam and going on an involved hunt, over the course of which Dean and Cas slowly figure out their feelings for each other. Lots of awkwardness (in a good way), some mild angst, comfort, and eventually fluff and smut.