You and your best friends are traveling around the world in a giant balloon. As you cross the Sahara Desert with its endless, golden sands, you spot a large silver dome in the distance. It looks like a flying saucer, but you can't be sure. Should you cut your journey short and investigate the mysterious object?

Illustrated by Don Hedin, credited as "Paul Granger", whose fanciful, cartoony illustrations help soften the blow of coming to a bad end. We don't know who did the cover. The book was reissued in the 1980's as Danger in the Desert.