This book tells a true detective story set mainly in Elizabethan London during the years of cold war just before the Armada of 1588. The mystery is the identity of a spy working in a foreign embassy to frustrate Catholic conspiracy and propaganda aimed at the overthrow of Queen Elizabeth and her government. The suspects in the case are the inmates of the house, an old building in the warren of streets and gardens between Fleet Street and the Thames. These include the ambassador, a Frenchman, his wife and daughter, his secretary, his clerk and his priest, the tutor, the chef, the butler, and the concierge. They also include a runaway friar, the Neapolitan philosopher, poet and comedian Giordano Burno. Others in the cast are Queen Elizabeth, her formidable secretary of state Sir Francis Walsingham, and King Henri III of France; poets, courtiers and scholars; statesment, conspirators, go-betweens and stool-pigeons. When not in London, the action takes place in Paris and Oxford; a good deal of it happens on the river Thames. The hero or villian, who calls himself Fagot, does his work most effectively, is not found out, and disappears. In the first part of the book these events are narrated. In the second the spy is identified and his story put together.