First published in April, 1910, "The Horse of the Invisible" tells the tale of Carnacki, a ghost detective investigating the haunting of a country house that threatens the wedding of the Hisgins Family's daughter and her fiance. The source of the apparition must be found before the soon-to-be-wed woman is driven mad, or even to her death. Carnacki does not suspect supernatural forces are at work in this case, but even a ghostbuster can be wrong.