Lenna has lived all of her eight years in a city called Kardum. Kardum used to be a normal city just like any other, but long before Lenna was born, the world turned upside down.

The earth is now where the sky used to be. And there is a dizzying drop into nothingness where the ground used to be.

The incident that everyone refers to as “The Rotation” has changed everything, but people have learned to get along in their upside down world. They move from house to house with the help of ropes and special gear. They enjoy simple lives without running water or electricity.

In fact, Lenna and her best friend Jaan have just the right amount of fun and excitement–until the supply of fresh water begins to run out.

Beneath the sky there is Mabal, a world built from all the things that have fallen from Kardum. There you don’t have to be afraid of falling into the sky anymore, but instead you have to worry about what falls from the sky: trash, sand, and even houses and boulders.

And there’s another danger. Mabal rests on a thin surface. Anyone who digs too deep below the surface will fall –no one knows where. That is no one, until Lenna and Jaan one day end up there: in the old Kardum that still lives in the age before the Rotation. When they realize that there is only a week to the Rotation, they have a choice to make: should they try to save the old world?