From the introduction: Investigators are all 'freaks' (used in its historical and colloquial sense to reflect contemporaneous attitudes). Each has taken part in the murder of two other Circus performers and is traumatized by it. The Circus is moving from town to town when one of the other freaks (Constance) starts to conduct sacrifices and ceremonies intended to bring about an earthly gateway to the Dreamlands that the Great Old One Atlach-Nacha can use.