Jake and Marisol thought they'd left the World Between Blinks behind forever, but their old allies—the explorers and Amelia Earhart—call them back for help. The Administrator has gone into overdrive, and his Curators are hard at work cataloging absolutely everything in the World. And in the Curators' quest to make sure everything's properly categorized, families are being torn apart and homes uprooted; everyone and everything is being treated like they're exhibits in a museum instead of being allowed to change and grow. But legend has it that the Administrator once lost something precious himself—a mysterious item known as the Rocket. They say it's why he became so obsessed with cataloging everything. Now, Jake, Marisol and their allies wonder if finding it might be the only way to convince the Administrator to stop, before everything that makes the World wonderful is lost in a whole new way . . .