Sleeping Dogs: a DCBB 2014 Elementary AU by dtkrushnics
Dean Winchester, surgeon turned sober companion, has been assigned his new client - the brilliant, if standoffish, Castiel Novak - for the next six weeks. What he expects is late night searches for needles and booze, playing chaperone to sobriety meetings, maybe the occasional stern talk or two. Instead, he finds himself working with Castiel for the New York Police Department. Feverishly helping to solve the case of the elusive M, an as-good-as-they-get serial killer who seems to be following Castiel around the globe, Dean and Castiel find themselves trapped in a cat and mouse game where the consequence of not being quick enough could be deadly.