City of Time (Navigator Trilogy Series #2)

Cati, The Bold Watcher readers met in The Navigator, returns from the shadows of time to summon Owen and Dr. Diamond, for time is literally running out. The moon is coming closer to the earth, causing havoc with weather, tides, and other natural cycles; people fear the world will end. To discover what's gone wrong, Cati, Owen, and the Doctor must take an astonishing journey to the City of Time, where time is bought and sold. There, Owen begins to understand his great responsibility and power as the Navigator.