13 - Czars Spy by William Le Queux

When the British Consulate in Leghorn falls victim to a puzzling burglary, and an enigmatic English yacht pays an unexpected visit, it sparks an enthralling journey of espionage and hidden criminal machinations. This thrilling tale sweeps the reader from London to Scotland, and finally to the oppressed lands of Finland, under the harsh rule of imperial Russia. Our protagonist is a man of exceptional acumen, a precursor to the likes of Double O Seven, who finds himself pushed to his limits as he navigates this web of intrigue and deception to uncover the truth. - Summary by Nicholas Clifford