A naïve plan to run away and cruel misfortune puts twelve-year-old Robert and his best friend Michael on a British naval vessel. When the boys are found huddling at the bottom of a lifeboat, they are forced into service and their hopes for an easy passage are crushed. Now they must figure out how to survive in this harsh maritime world and find a way out, without getting shot as deserters.
 
Horrible squalls, a mysterious initiation at the Equator, and an untimely death during a perilous rounding of Cape Horn fill the months with adventure. An unexpected opportunity to escape suddenly presents itself and the boys muster the courage to desert. Immediately, they are lost in a dense and dangerous jungle and must learn a new way to stay alive