In 1928, nine-year-old investigator Lottie and her friends try to save the British Museum from shuttering its doors by looking for a buried treasure in a secret tunnel beneath the museum, only to discover they must solve a series of puzzles to find the treasure as well as their way out of the maze of passageways.

"First published 2016 by Bloomsbury Education, an imprint of Bloomsbury Publishing Plc."--Title page verso.