How do you vanish a family?

Ten minutes after walking the elite Back Bay townhouse and investigator Tessa Leoni already doesn?t like what she sees.

Before the multi-million, runaway bestseller The Da Vinci Code, Dan Brown set his razor-sharp research and storytelling skills on the most powerful intelligence organization on earth–the National Security Agency (NSA), an ultra-secret, multibillion-dollar agency many times more powerful than the CIA.
When the NSA’s invincible code-breaking machine encounters a mysterious code it cannot break, the agency calls 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 would cripple U.S. intelligence.