On Arborium, the last forested island in the future, fourteen-year-old Ark, who lives in a mile-high city set in the tree tops, overhears a plot to rob Arborium of its wood, a natural resource more precious than gold.

• ISBN: 9780545305501
• Author: Peters, Andrew
• Published: 2011 , Scholastic Inc.
• Themes: Adventures, conservation, Trees
• Descriptors: England (UK), Europe, Intermediate (ages 9-14), Science Fiction
• No. of pages: 368