[1] The book concerns the adventures of Emily Hayes, who must try to rescue her kidnapped mother with the assistance of her younger brother Navin, a mysterious amulet, and helper robots such as Miskit.

While exploring Silas's library, Emily finds a stone amulet that had been hidden in a table, and Navin helps tie it around her neck.

A noise from the basement awakens the family from where they have sleeping on the floor of the house until it can further be renovated, and as they enter to investigate, Karen is kidnapped by a large beetle-like monster with tentacles.

As the children hide from the monster, the amulet tells Emily that to save their mother they must find the house where Silas lives.

Now deep underground, the children see a house on a column of rock surrounded by water, at the bottom of an enormous hole overhead leading to the surface.

After Silas dies, the lights turn off and the amulet glows and tells Emily to become the new stonekeeper and accept its power, which she does against Navin's wishes.

Upon the book's release, Booklist stated that the "action-packed adventure sequences move at an exciting clip," but that there were "dark elements in the tale.

"[5] On the other hand, one reviewer for School Library Journal felt a "sense of déjà vu in some scenes" and concluded that the book was "serviceable, but not extraordinary.

"[9] In 2010 it won a Rhode Island Children's Book Award and was included in a Library Journal list of 33 "Graphic Novels for Reluctant Readers.