The Traitor's Daughter — Barbara Kyle

In 1582, England is gripped by the fear of traitors. Kate Lyon, tainted by her exiled mother's past treason, has been disowned by her father, Baron Thornleigh. But in truth, Kate and her husband Owen are only posing as Catholic sympathizers to gain information for Queen Elizabeth's spymaster. Kate is an expert decoder. The deception pains her, but she takes heart in the return to England of her long estranged brother Robert. If only she could be sure where his loyalties lie...

Kate and Owen's spying yields valuable intelligence: English Catholics abroad are spearheading an invasion that would see Elizabeth deposed -- or worse -- in favor of Mary, Queen of Scots. Kate takes on the dangerous role of double agent, decoding and delivering letters the exiles send Mary. But when lives and fortunes hang by the thinnest threads, betrayal is only a whisper away...

A brilliant blend of Tudor history and lush storytelling, The Traitor's Daughter is a riveting, passionate novel of loyalty, heartbreak, and one woman's undaunted courage.