In a future where Earth is covered by a deadly, intelligent Fog, people live on mountaintop slums. Thirteen-year-old Chess and his crew of salvage-scavenging orphans work for the cruel Lord Kodoc. Chess possesses a rare ability to dive into the Fog without dying, searching for valuable tech from the old world. When they discover a map that might lead to a mythical safe haven called Port Oro, they must embark on a dangerous sky-ship adventure, outsmarting Kodoc and the Fog itself to find freedom.