The setting is the years prior to the outbreak of World War I. It is a time when Germany is outwardly preparing for war but Britain continues to believe it is invincible and that no one would challenge her. A vast German spy network flourishes in England, often in plain view. The main character is Francis Norgate, an aspiring British diplomat who falls in disfavor with his superiors for defending a woman while stationed in Berlin. The resulting scandal causes Norgate to be recalled. On the way home, he meets a German gentleman, Selingman, who claims to be a crockery salesman...

A conference of European nations is being held in the Hague. England has not been invited to attend. Some think war is about to break out. Mr. John P. Dunster, an American, is traveling to the Hague with an important document that may prevent the outbreak of war when he mysteriously disappears after a train wreck in England. Richard Hamel is asked by the British government to attempt to solve the mystery of Dunster’s disappearance and prevent the outbreak of war in Europe.

Monsieur Lecoq is a captivating mystery, historical and love story: Around 11 o'clock, on the evening of Shrove Sunday 18.., close to the old Barrière d'Italie, frightful cries, coming from Mother Chupin's drinking-shop, are heard by a party of detectives led by Inspector Gévrol. The squad runs up to it. A triple murder has just been committed. The murderer is caught on the premises. Despite Gévrol's opinion that four scoundrels encountered each other in this vile den, that they began to quarrel, that one of them had a revolver and killed the others, Lecoq, a young police agent, suspects a great mystery...