Dunwich is based on the themes in H. P. Lovecraft's The Dunwich Horror and is the continuation of Peter Levenda's novel The Lovecraft Code.

Beginning with the harrowing experience of an alien abductee in a small New England town and continuing through a series of encounters with a renowned mathematician, mercenary geneticists, an international ring of pornographers, the human trafficking cult of the Islamic State, and practitioners of an arcane form of sexual occultism, Dunwich follows the adventures of religion professor Gregory Angell as he attempts to discover a shocking secret encoded within an ancient book of magic that, once deciphered, will cause the eruption of a force so prehistoric that its earthly temples—once submerged beneath the seas—will rise to the surface again.