When the National Security Agency's invincible code-breaking machine encounters a mysterious code it cannot break, the agency calls in its head cryptographer, Susan Fletcher, a brilliant, beautiful mathematician. What she uncovers sends shock waves through the corridors of power.
The past has a habit of tracking us down. And tripping us up.
When Kate was twenty-two, she had an intense and passionate affair with a married man, Callum, which ended in heartbreak. Kate thoug...