A thrilling adventure on the other side of the Cthulhu Mythos: in a handful of dust... As the ancient war between the old gods of Earth and their bitter enemies rises toward a final confrontation, Owen Merrill sets out from his new home in Arkham to Rhode Island, seeking the ultimate weapon in that war: the spells that might succeed in calling Great Cthulhu from his temple-tomb in drowned R'lyeh to fulfill the terrible prophecy of the Weird of Hali.

The threads of evidence he and Jenny Chaudronnier have traced through years of hard work all lead to a young man named Charles Dexter Ward, who lived in Providence a century earlier and may have received copies of the rituals from the elderly scholar George Gammell Angell.

As he plunges into the mysteries surrounding Ward and the rituals, he finds himself entangled in a web of peril reaching far beyond the urban landscape of Providence.

The Starry Wisdom Church there is racked by rivalries no member will discuss, and the Radiance and the Fellowship of the Yellow Sign are closing in.

Owen's one hope lies with a young woman named Hannah Ward-Charles Dexter Ward's great-granddaughter-who is in Providence on a mission of her own.

She has learned the same terrible secrets of alchemy her great-grandfather mastered, and plans on using them to revive the one person on Earth who might know the location of the rituals Owen needs so badly: Charles Dexter Ward himself...