I really enjoyed this! Total AU, All Human. Kate happened, in a way. She was bipolar, burned Derek's house down, nobody died though. After this, and a couple of other bad things, he is understandable wary of relationships.
Today is a no good horrible very bad day for Derek. His roommate is moving in with his girlfriend, leaving him either needing a new roommate or a cheaper place, his car breaks down on his way to work, a situation with Kate rears it's very ugly head, and now he's caught out in the rain on his way home. He breaks down, then meets Stiles, and magic happens.
This was kinda instalove, but it felt real. One of those connections that just come out of nowhere and smacks you in the heart. It just felt really well done for me.