When Ranjit Subramanian, a Sri Lankan with a special gift for numbers, writes a three-page proof of the coveted "Last Theorem," which French mathematician Pierre de Fermat claimed to have discovered (but never recorded) in 1637, Ranjit's achievement is hailed as a work of genius, bringing him fame and fortune. But it also brings him to the attention of the National Security Agency and a shadowy United Nations outfit called Pax per Fidem-or Peace Through Transparency-whose secretive workings belie its name. Suddenly Ranjit-along with his family-finds himself swept up in world-shaking events, his genius for abstract mathematical thought put to uses that are both concrete and potentially deadly.