11 year old Nim lost her mother as an infant. Since then she has lived alone with her father, marine biologist Jack Rusoe, on an isolated island in the South Pacific. There are no other human beings on the island, but Nim has developed a close relationship to the sea lion Selkie, the lizard Fred, and the pelican Galileo - and to fictitious characters in her favorite novels. When Jack goes out in his boat to find new nanoplanktons, Nim stays alone on the island. A devastating storm is coming, Jack loses his cell phone, and after a couple of days Nim fears that something terrible has happened. Via email she begs the fictitious hero Alex Rover to come and help her. What Nim doesn't know is that the real person she contacts is the female author Alexandra Rover. She is a borderline agoraphobic, who hasn't left her house in San Francisco for 16 weeks. Trigged by her fictitious character Alex Rover, Alexandra at last starts the long journey by airplane, boat and helicopter to reach Nim. In the meantime tourists from a luxury cruiser invades Nim's island. Nim uses all possible means to fight them, and succeeds to drive them away before Alexandra finally arrives to the island. Together they wait for news about what has happened to Jack .