The mysterious Count D is the proprietor of a pet shop in Los Angeles' Chinatown. Each of D's rare pets, which all have strangely humanoid appearances, comes with a contract which can have severe consequences if broken. his shop becomes the subject of an ongoing investigation carried out by Detective Leon Orcot, who usually spends his free time lurking around the shop drinking tea and eating sweets with d and his strange menagerie. The chapters are usually stand alone stories, each dealing with a new pet and it's owners, and the tragedies that befall them when they fail to heed D's careful warnings.
This is an excellent manga for manga fans in general, and especially great for fans of the dark and macabre. The art is lush and detailed, the character design unique and eye catching and the stories range from horrifying to touching in turns. the sequel isn't as good as the original but it's also worth a look. you can read them all online here-