In her third gripping adventure, Nim unearths an amazing opalized fossil, but this discovery puts her island in terrible danger. Nim lives on an island with her father, Jack, a marine iguana called Fred, a sea lion called Selkie, and their friend Alex Rover, the adventure writer. Nim's island is the most beautiful place in the world, and she wouldn't live anywhere else. When Jack invites a group of scientists to visit, they bring their children as...