Thomas Carnacki was a consulting detective who frequently investigated occult and supernatural occurences. He lived in a flat on Cheyne Walk in Chelsea, and he kept a library on the occult, which included the Sigsand Manuscript, which helped to protect him against supernatural dangers. He was assisted by a friend named Dodgson. Carnacki faced a variety of supernatural menaces and he categorized spirits as Aeiirii and the more dangerous Saiitii.