Clean And Clear

It's living in the vast sewers, whatever "It" is. Living there, hunting there, and devouring any human it can get it's hands on down in the dark. In the disgusting, murky waters of London's Sewer System, It calls home. Hiding. Waiting. And Sherlock is just the consulting detective to flush it out. (Dark!Mer Fantasy AU - Merlock With A Twist)