Millions of years in the Earth's future, humans have long vanished from the planet. Evolution has produced a host of wondrous and intelligent beings: shape-shifting Fantastic Grouts with globes of light atop their skulls; creatures descended from flowers; and massive swarms of bees that can bore perfect holes through metal or bone. But some seek a way to bring the humans back into the world-a world filled with creatures like twelve-year-old Tully, a young, amphibious Eft who imagines humans as nothing more than old bones and fairy stories. When his beloved guardian is stolen by a menacing black shadow, Tully must embark on a journey to a cruel, northern land to save her and his entire species. In an adventure that blends time travel, magic, and science, Tully learns whom he can trust, and who will betray him-for the price of reawakening the Hundred.