The Elizabethan navy has a secret weapon: an optical instrument so powerful it gives England unassailable superiority at sea. Spain will stop at nothing to steal it and seize the two men who understand its secrets - its operative William Ivory, known as the 'Queen's Eye', and its inventor, the maverick magician Dr Dee. With a second Armada threatened, intelligencer John Shakespeare is sent north to escort Dr Dee to safety. But his mission is far from straightforward. Dee's host, the Earl of Derby, cousin to Elizabeth, is dying in agony, apparently poisoned. Who wants him dead and why? What lies behind the lynching of the recusant priest Father Matthew Lamb? And what exactly is the connection between these events and the mysterious and beautiful Lady Eliska? While Shakespeare attempts to untangle a plot that points to treachery at the very highest reaches of government, he also faces serious accusations far closer to home. With so much at stake, must he choose between family and his duty to Queen and country? Moving from the Catholic heartlands of Lancashire to a vagabond camp in the heart of England, and from the deck of Admiral Frobisher's flagship off the Brittany coast to the secret meetings of Elizabeth's closest associates, Traitor is award-winning writer Rory Clements' most intriguing and compelling novel to date.