Follows a fourteen-year-old American girl whose life unexpectedly transforms when she moves to London in 1952 and gets swept up in a race to save the world from nuclear war.

Four years after Alfie Summerfield's father left London to become a soldier in World War I he has not returned but Alfie, now nine, is shining shoes at King's Cross Station when he happens to learn that his father is at a nearby hospital being treated for shell shock.

Bertie Bradshaw never set out to become a spy. He never imagined traipsing around war-torn London, solving ciphers, practicing surveillance, and searching for a traitor to the Allied forces. He certainly never expected that a strong-willed American girl named Eleanor would play Watson to his Holmes (or Holmes to his Watson, depending on who you ask). leaving behind a coded notebook, Bertie is determined to solve the mystery. With the help of Eleanor...