黑山羊~献给小羊们的小夜曲~

Late 19th century. In a certain place in Western Europe there was a famous house called the Yagi family. Lord Earl was an excellent person as its head. · · · However, one day the he disappeared. An incident occurred in which all members were found dead. The crime remained unsolved. 100 years have passed since then · · · A certain detective tried to bring the truth about this incident up without a request from anyone and vanished without a trace. His best friend is anxious to know about his whereabouts and he steps into the mansion as well. He seems to be a very ordinary journalist, but in reality he has a "witch" as his ancestor.