Cody Chang's San Francisco store could be considered creepy - Skin & Bones sells animal skulls, fish skeletons, reptile skins, and more. Business is booming, but when Frank and Joe visit the shop, Cody tells them he's been the victim of a string of burglaries, computer thefts, and threatening messages.
The Hardy's immediately pinpoint a suspect - a criminal who ha caught in a sting by Cody's father, a policeman. Now there's danger everywhere for Frank and Joe - from a cable car accident tot he dense redwood forests of Muir Woods to the foggy, ice-cold waters of Alcatraz. The brothers are running hard and thinking fast - up against a smart, desperate enemy ready to skin them alive.