Kuroshitsuji fanfic- " The Black Death"

A kuroshitsuji fanfiction - Ciel and Sebastian must find out why everyone in London is suddenly becoming extremely ill and dying as well as solve the problem. But things won't be that easy to solve even for Ciel and Sebastian. Will they be able to find out who is behind the disease? Could Ciel himself fall victim to it?
Possible OOCness and maybe CielxSebastian in later chapters though at this point I feel it would detract from the story line.
No copyright infringement intended all characters and settings belong to their respective owners though the storyline comes from my imagination.Cover image found on google images,I added the words.