During the decline of the Victorian dynasty in Britain in the 19th century, the upper class society to which the British royal family and nobles belonged was filled with blood and darkness. Money, greed, power, family marriage, red wine as strong as blood in a glass goblet, gorgeous and expensive gems and silk.
The nobles who are addicted to this, Ernest, Phantomhive, and Trincy, use their power and various interpersonal connections to maintain this gorgeous and decadent stage that is about to collapse. Sweep away the so-called traitors and let Britain, which is filled with sticky darkness, be stained with strong blood again. Carrying the mission of "The Queen's safety is above all else, we will get rid of the Queen's worries", and at the same time carrying the curse of the family - a sin that can never be escaped...