Traces the life of Elizebeth Smith, who met and married groundbreaking cryptologist William Friedman and worked with him to discover and expose Nazi spy rings in South America by cracking multiple versions of the Enigma machine.

Thirteen-year-old Dan Cahill and his older sister, Amy, thought the search for the thirty-nine clues leading to the source of their family's power was over, but when Cahills are kidnapped by the Vespers, Amy and Dan find themselves with only a few day to fulfill a bizarre ransom request before their friends start dying.