"This might be Hautman's most daring book yet. . . . Well-developed and complex characters, a fascinating time-travel framework, and a heart-stopping conclusion." -- Publishers Weekly (starred review) Tucker Feye's family has disappeared. He suspects that the disks of shimmering air he keeps seeing -- one right on top of the roof -- hold the answer to finding them. But when he dares to step into one, he's launched on a time-twisting...