In the second half of the 19th century, in the Victorian era of Britain, the protagonist is the butler of the family of the famous aristocrat Fadom Hein, Sebestian. He is the embodiment of knowledge, education, taste, cullinary, martial arts...and holds eighteen skills himself. It can be said that he is a butler with no shortcomings. The master he served was a wayward 12-year-old Charles. Today Sebastian is also wearing a jet black tuxedo and performing his mission gorgeously......

In the 19th century, Alois, the patriarch of the famous Trancy family, was a beautiful boy with blond hair and blue eyes. Not long after he was born, he was abducted by the "elves,” and it was not until a few years ago that he and the "black butler" Claude returned to Trancy's house together. Claude is absolutely loyal to his master and is always by his side to accomplish various tasks gracefully. But apart from his name, no one knows Claude's past. As for the uncle of Alois, he is always too lazy and regards money as fate. For their own benefit, they started to doubt their identities....