In this high-stakes duology closer from New York Times bestselling author Margaret Peterson Haddix, Maisie finds out she's the last moonleaper—unless she can figure out how to change past events to secure the moonleapers' legacy.

Maisie was thrilled to become a time-traveling moonleaper and help her Great-Aunt Hazel fix the past—catapulting everyone in the world into a better timeline. But now Hazel’s gone, time is glitching, and the only other moonleaper Maisie knows appears to be in grave danger. Then a mysterious boy named Krieger shows up. Maisie is immediately suspicious because he seems too interested in her secrets. But as it turns out, he has a few secrets of his own. Could working together be the key to fixing time and saving Maisie’s friend Ainsley—or will that doom all of humanity to an unbearable future? The clock is ticking, and it’s up to Maisie make things right. Or else the moonleapers—and Maisie herself—could be erased from time…forever.