Meg­gie Keny­on is a twelve-year-old girl liv­ing in France under Nazi occu­pa­tion. Her father left home to fight the Ger­man army in 1940, and when the book opens in 1942, his fate is unclear. Jen­nifer A. Nielsen explores the impor­tant role that cryp­tog­ra­phy played dur­ing World War II in devel­op­ing an engross­ing plot for young read­ers, as Meg­gie attempts to turn her inter­est in secret codes into a form of active resistance.

Meg­gie and her father, Harp­er Keny­on, have always been close. They read poet­ry togeth­er and par­tic­u­lar­ly enjoy cre­at­ing and solv­ing codes. But when her British father leaves to ful­fill his com­mit­ment to fight­ing fas­cism, their past togeth­er becomes a way for Meg­gie to sur­vive the present and to have hope for a future. Her moth­er, Sylvie, is French, as is Meggie’s grand­moth­er, whose farm becomes their home when Harp­er Keny­on dis­ap­pears. Meg­gie is at home in both the Eng­lish and French lan­guages. Even the way her moth­er pro­nounces her name, which is short for Mar­garet, is evi­dence of the dif­fer­ence between her par­ents and the way in which she shares much in com­mon with both of them.

Once it becomes clear that Meggie’s father is not the only mem­ber of the fam­i­ly to be engaged in dan­ger­ous resis­tance activ­i­ties, she decides to take an active role as well. Her par­ents’ val­ues encour­age her brav­ery, but the dai­ly risks and fright­en­ing events in her life cre­ate dra­mat­ic ten­sion in the sto­ry. Most chap­ters begin with a rule, a brief epi­gram­mat­ic expres­sion that frames her mis­sion to save a fam­i­ly of refugees, Liesel, Jakob, and Albert and to find her father. ​“Peo­ple are indi­vid­u­als, not cat­e­gories,” and ​“Every­one has rea­sons for the things they do” may seem like philo­soph­i­cal state­ments, but they are also prac­ti­cal clues about how to con­front the dilem­ma she is try­ing to resolve. Meg­gie needs to con­stant­ly read­just her assess­ments of peo­ple and also to imag­ine dif­fer­ent solu­tions to the ver­bal codes that she hopes will lead her to success.

The Jew­ish con­tent of the book remains in the back­ground. No char­ac­ters are Jew­ish, but Meg­gie is ful­ly aware of the arrest and depor­ta­tion of Jews in France. Watch­ing help­less­ly as peo­ple who had believed they were safe in France are aban­doned by their neigh­bors, she becomes embit­tered at how quick­ly and eas­i­ly the Nazis had been able to occu­py France and impose their racial laws. As she real­izes with irony, ​“Our gov­ern­ment in Vichy protested…but only because the Ger­mans had not gone far enough.”

Read­ers will share Meggie’s sense of urgency as she scru­ti­nizes the pos­si­ble mean­ings of each word in a let­ter, know­ing that it is intend­ed to instruct her about her mis­sion. Deci­pher­ing codes, as well as unrav­el­ing the mys­ter­ies of peo­ple, lead her to her work’s conclusion.

The book includes a sec­tion on secret codes and back­ground infor­ma­tion about the British Spe­cial Oper­a­tions Exec­u­tive dur­ing World War II.