For 17-year-old Lauren Hudson, reluctantly helping her senile grandmother during a crisis turns from bad to worse when she is marooned with her annoying younger brother on remote Mackinac Island, Michigan. But Lauren's misery is interrupted by the discovery of clues to a generations-old family mystery, and her brother, normally bent on pushing her from irritated to insane, proves to be the perfect partner in a modern-day treasure hunt. But are they the hunters or the hunted? Grandma's dire predictions and fear for the Hudson children's safety proves not so crazy after all. Misplaced items, disappearing food, and unexplained noises become more than an inconvenience, and soon Lauren and Adam find themselves in a race for riches--and their lives.