The first time his father disappeared, Tucker Feye had just turned thirteen. The Reverend Feye simply climbed on the roof to fix a shingle, let out a scream, and vanished -- only to walk up the driveway an hour later, looking older and worn, with a strange girl named Lahlia in tow. In the months that followed, Tucker watched his father grow distant and his once loving mother slide into madness. But then both of his parents disappear. Now in the care of his wild Uncle Kosh, Tucker begins to suspect that the disks of shimmering air he keeps seeing -- one right on top of the roof -- hold the answer to restoring his family. And when he dares to step into one, he's launched on a time-twisting journey -- from a small Midwestern town to a futuristic hospital run by digitally augmented healers, from the death of an ancient prophet to a forest at the end of time. Inevitably, Tucker's actions alter the past and future, changing his world forever.