"Summer, 1940. Nineteen-year-old Jakob Novis and his quirky younger sister Lizzie share a love of riddles and puzzles. And now they’re living inside of one. The quarrelsome siblings find themselves amidst one of the greatest secrets of World War II--Britain’s eccentric codebreaking factory at Bletchley Park. As Jakob joins Bletchley’s top minds to crack the Nazi’s Enigma cipher, fourteen-year-old Lizzie embarks on a mission to solve the mysterious...