Thirteen-year-old Sable Winters has spent her entire life in the valley, forbidden by her overprotective father from ever climbing the mountains that surround their village. But when she discovers her late mother's journal detailing impossible balloon flights to floating islands above the peaks, everything changes. With help from Bridger, a boy who builds contraptions from salvaged parts, and Elowen, a mysterious girl who claims the sky itself speaks to her, Sable reconstructs her mother's hot air balloon and launches into the unknown. Above the clouds, they find the Drift Cities, civilizations that exist on islands suspended by ancient magic. But the islands are falling, and only Sable's mother knew why. Now Sable must finish what her mother started before the sky cities crash into the mountains below.
