In the spring of 1936, horror writer H.P. Lovecraft is broke, living alone in a creaky old house and deathly ill. At the edge of a nervous breakdown, he hires a personal assistant, Arthor Crandle. As the novel opens, Crandle arrives at Lovecraft's home with no knowledge of the writer or his work but is soon drawn into his distinctly unnerving world: the malevolent presence that hovers on the landing; the ever-shining light from Lovecraft's study, invisible from the street; and visions in the night of a white-clad girl in the walled garden. Add to this the arrival of a beautiful woman who may not be exactly what she seems, and Crandle is pulled deeper into the strange world of H.P. Lovecraft (a man known to Crandle only through letters, signed "Ech-Pi"), until Crandle begins to unravel the dark secret at its heart.