A young girl finds herself faced with an impossible choice-run away from her beloved valley, or unleash a hidden magic and become a Mapmaker to save her home from its new overlords. For centuries, the Mapmakers kept peace in the Valley, but they've long since disappeared. Now the Night Coats hold power with an iron grip-there are only rules, punishments, and consequences. Until one night, on the run from the Night Coats (again), after breaking another rule (again), Alidade stumbles upon a secret door leading to a magical hideaway that belongs to the Mapmakers. There, she finds a map of her home, and accidentally brings to life Blue, a magical creature called a memri who is meant to protect the Valley. Blue needs Alidade's help to find the Mapmakers and save the Valley from the Night Coats! But the Mapmakers are long gone. Alidade has a choice: leave the Valley like she's always wanted…or become a Mapmaker and save the only home she's ever known.