From a village made of hot-air balloons to a subterranean battle arena, two young people struggle to discover who and what they are - and how to use the astonishing powers they share.High over China, the Sky Village - an intricate web of interconnected hot air balloons - floats over a troubled landscape where animals and machines battle for control.

Twelve-year-old Mei has been left in this strange place by her father, who insists on going alone to try and rescue her kidnapped mother.

Meanwhile, half a world away, thirteen-year-old Rom struggles to survive in the ruins of Las Vegas.

Mei and Rom have never met, but they share a common journal, a book that mysteriously allows them to communicate with each other.

It also reveals that they carry the strange and frightening Kaimira gene.