A team of CIA operators went to a secluded airfield, boarded an old Soviet-made Mi-17 transport helicopter, and swooped toward the jagged, snow-draped peaks of northern Afghanistan.

Their aim was to revive secret intelligence and combat operations against bin Laden in partnership with guerrilla commander Ahmed Shah Massoud, leader of the Northern Alliance, a ragged coalition of Afghan fighters, many of them veterans of the war against the Soviets. Massoud's hardened militiamen clung to their positions in the stark Panjshir Valley.