Kids who are enthusiastic about codes may want to try decoding the messages that are referred to in the text and can be found (along with worksheets) within the distinctive illustrations. While Nana’s work at Bletchley may not be meaningful to children too young to understand the context, codes and secret messages have an enduring appeal for many children. - Carolyn Phelan; Booklist Reviews

Charlotte loves puzzles. On her ninth birthday, she receives a card from her great-grandmother, on which she finds a difficult code. Soon she embarks on a quest full of codes and riddles. While she tries to solve them, Charlotte discovers important details about the role her great-grandmother played in the Second World War. She also learns about three historical sites in England: Parker’s Piece, the River Cam, and Blechley Park. You’ll learn about these places, too! 

A surprising picture book about history and code language. For codebreakers ages 6 years and up.