1588. In Lisbon the great Spanish Armada prepares to set sail for England. Along the coast of the Low Countries, the army of the Duke of Parma readies itself for embarkation. Threat is imminent. Yet behind it is a darker and more secretive game, one of espionage and murder, of trechery and deceit. The stiletto-blade to the back, the poison in the chalice, the torturer's rack in the dungeon. This is the realm of the spy. And at its heart is the legendary Elizabethan spymaster Sir Francis Walsingham. One-by-one his intelligence sources vanish, day-by-day the danger to his queen and country grows.