*Book is used and in Very Good condition.
*Has some spine and cover creases.

When the NSA's most classified technological wonder--an invincible code-breaking machine--encounters a mysterious code it cannot break, the agency calls in its head cryptographer, Susan Fletcher, a brilliant and beautiful mathematician. What she uncovers sends shock waves through the corridors of power.

The NSA is being held hostage... not by guns or bombs, but by a code so ingeniously complex that if released it will cripple U.S. intelligence.

Caught in an accelerating tempest of secrecy and lies, Susan Fletcher battles to save the agency she believes in. Betrayed on all sides she finds herself fighting not only for her country, but for her life, and in the end, for the life of the man she loves.