The Slaves of Paris by Emile Gaboriau

The danger with which André was menaced was most terrible, and the importance of the game he was playing made him feel that he had everything to fear from the boldness and audacity of his enemies. He knew this, and he also knew that spies dogged all his movements. What could be wanted but a favorable opportunity to assassinate him. But even this knowledge did not make him hesitate for an instant, and all his caution was fully exercised, for he felt that should he perish, Sabine would be inevitably lost. On her account he acted with a prudence which was certainly not one of his general characteristics. He was quite aware that he might put himself under the protection of the police, but this he knew would be to imperil the honor of the Mussidan family. He was sure that with time and patience he should be able to unravel the plots of the villains who were at work. But he had not time to do so by degrees. No, he must make a bold dash at once. The hideous sacrifice of which Sabine was to be the victim was being hurried on, and it seemed to him as if his very existence was being carried away by the hours as they flitted by. He went over recent events carefully one by one, and he strove to piece them together as a child does the portions of a dissected map. He wanted to find out the one common interest that bound all these plotters together -- Verminet, Van Klopen, Mascarin, Hortebise, and Martin Rigal. As he submitted all this strange combination of persons to the test, the thought of Gaston de Gandelu came across his mind.

"Is it not curious," thought he, "that this unhappy boy should be the victim of the cruel band of miscreants who are trying to destroy us? It is strange, very strange."