The author of Tough Tiffany and A Girl Called Boy creates another self-reliant character: Savannah Guthrie, 12, whose father is a poor fisherman on North Carolina's Outer Banks. Savannah is haunted by the idea of the Nightwalker--the self's other spirit that her Indian ancestors believed walked abroad during sleep. Her worries are complicated by a series of fires that are being set on Shackleford, a neighboring island being developed by the US Park Service, perhaps in protest against the development--or is little brother Poco, a habitual sleepwalker, implicated? Savannah's conscience is not quite clear here: she and Poco used to play a dangerous game with fire. Hurmence sustains the suspense while blending the threads of her mystery with a strong sense of place--as well as with the less-than-smooth development of Savannah's friendship with the wealthy doctor's daughter whose weekend home next door is on the property her father had hoped to buy and develop as a marina. The solution isn't surprising; but it's plausible, and nicely dramatizes both the social issues and Savannah's realization that she too has been a ""sleepwalker."" A satisfying story, told in a simple yet notably lyrical style.