Hermann Wolff, a Wehrmacht Colonel assigned to German's intelligence agency, the Abwehr, investigates a suspicious train crash on the outskirts of Berlin with his right-hand man, Lieutenant Johann Bauer. Among the belongings of one of the bystanders is one of a spy's standard tools of the trade. When interrogated, its owner claims to have stolen it from a Japanese man named "Maki Katsuhiko..."
If you wrote a message with these 
and applied the right chemicals,
إن كُتبت رسالة بهذه وأخضعناها 
،لمواد كيميائيّة معيّنة
Wenn Sie damit eine Nachricht schrieben
und man die richtigen Chemikalien auftrüge,
Si los usaras para escribir, 
las letras se harían visibles
Si las usaras para escribir, 
las letras se harían visibles
Tu écris avec, et ensuite,
il suffit d’appliquer un produit
Un messaggio scritto con questi
potrebbe poi essere reso visibile
É possível escrever uma mensagem invisível
com eles e, usando a reação química certa,