England, 1586. Tensions rise as threats to the realm abound. Traitors are plotting for Mary Queen of Scots to depose Elizabeth I and take the throne. Rumors of a Spanish invasion by sea mount daily. And the body of one of Sir Francis Walsingham's agents is found floating in the Thames as other agents face enemies armed with crossbows and vials of poison.

Nicholas Holt, a spy in Walsingham's employ, narrowly averts the same fate while setting off in pursuit of the killer--or killers. And when he surprises a suspect in the company of a Spanish agent, he believes he's close not only to solving the case but preventing an act of high treason.

But soon, the attacks begin to threaten Nick's circle of friends. As those he loves face mortal peril, Nick must unravel the tangled plot, all the while steering a careful path through the fierce rivalry between Walsingham's agents and those of the Queen's favorite, the upstart Earl of Essex. Now it's a race to the breathless conclusion as Nick desperately searches for the answers that can save the day--and a vestige of loyalty that can save his own life.