The Queen's conjurer, Doctor John Dee, is an Elizabethan mathematician, cryptographer, and mystic commissioned by Her Majesty's spymaster, Sir Francis Walsingham, to suss out a noble Count who governs an island in the English Channel. Dee's mission? Uncover treason, reveal terrorists, and unveil threats to The Crown. Embarking, Dr. Dee is accosted by an eager acolyte. The unknown teen playwright, William, has just endured his first flop-Prince Amleth. Will solicits the renowned scholar's mentorship. A winter tide sees these unlikely collaborators set sail for the Channel Islands to sleuth out sedition on Protestant England's strategic outpost. On Illyria, clues appear as Dee comes to rely on the surprising ingenuity of his young companion. Clandestine powers collide as Queen Elizabeth's spy tracks each slim lead. When Dee is brought to the brink of destruction, can his incipient discovery of Count Orsino's recusants and loyalists be thwarted?