The dangers of global warming come to the fore with this tale, which centers around Mara Bell. She is a 15-year-old girl growing up on Wing, a quickly-shrinking island set in the North Atlantic. There are clues that Wing used to be a much bigger piece of land, but the melting of the ice caps more and more each year has led to rising oceans that are eating into her village.

After a series of particularly warm summers, the island experiences a challenging wet season that brings about what is clearly the end of their ability to live on the island. There have always been rumors of the Sky-Cities, man-made islands that people fled to over the years as the environmental catastrophe developed. Unfortunately, everyone on Wing has feared that they were just myths. As a result, no one has been brave enough to take their small fishing vessels out to sea to find one of the cities. Now, they have no choice.

After a challenging sea voyage, Mara and the others who did not have to be left behind arrive at the wall of one of the cities only to find that they are not really welcome. They have no choice to do what they can to get in and survive, but it is only accomplished through a series of trials that pick at their numbers.

This book is like a junior version of Waterworld, which was produced by Kevin Costner a number of years ago. Many of the themes are similar even as the story is set around a younger cast of characters. The writing style is strong, and I could not help buy find myself comparing it to Lois Lowry, particularly in relation to Gathering Blue and The Giver, two companion dystopian novels. The only problem I see with the book is that it is pretty slow moving. As a result, it is probably significantly longer than it needed to be, which will cost it a number of readers.

The book is particularly timely, as we see the leader of Micronesia looking to purchase land on the mainland to house his peoples as the islands making up their country disappear into the ocean because of rising seawaters.