In this follow-up to the internationally successful The Mapmakers' Race, the Santander children are drawn into a community’s rebellion against a despot and use their mapping skills to avert an environmental scam.

Sal, Joe, Francie and Humphrey Santander are mapmakers looking for their father, a famous explorer who disappeared on his last expedition. Their search takes them to Cruxcia, where the people are fighting to protect their land from the all-powerful Grania Trading Company. The Santanders’ mapping skills may be the missing piece in the Cruxcian race to save the ancient valley—and the key to reuniting their family.

• Part detective story and part adventure 
• Resonant contemporary themes: revolution, environment, indigenous land ownership 
• Follow-up to the internationally successful The Mapmakers' Race: widely reviewed, strong sales, chosen for the Summer Reading Challenge 2021 in the UK, Indie Booksellers Summer reading catalogue 2019 Australia, an IBBY Honour Book