"Of course not; but who knows that he returned it? You, I, Manuel, Vass, and Donna Maria, not Leighbourne. Depend upon it, Mr. Darrel, we'll have Leighbourne in gaol to-morrow night, and this mystery which has baffled us for so long, will be at an end." "Well," said Darrel thoughtfully, "your argument is ingenious. Let us hope it will prove true." "Wait till to-morrow night," said Torry drily, and took his leave, satisfied that he was the smartest detective in London, and the cleverest man in the wide world. Darrel passed the rest of that day, and most of the next, in speculating on the probable result of this expedition. He could not deny that Torry's theory was ingenious and feasible, but thought that he was too sanguine. It seemed madness that a man guilty of a double crime should thrust himself willingly in the way of danger and risk betrayal. To be sure, he knew that Vass had stolen the money, and believed that he still had it in his possession, so he, no doubt, believed that terror of arrest and the desire to keep his spoil, might influence the secretary in holding his tongue. If the assassin knew that the money had been returned, and that Vass had repented of his iniquity, he might have been chary of risking a meeting; but he was ignorant, and therefore, rash, and there was every probability that he would be arrested. With arrest would come confession, and so the mystery of the dual crime would be solved. Still, the truth had evaded detection so many times, that Darrel could hardly bring himself to believe that it was about to be brought to light. He thought it possible but improbable. The next night, shortly after ten o'clock, he met Torry, who was accompanied by two constables in plain clothes, and the four men walked to Hyde Park. The night was moonless, but there was a faint glitter of starlight, and a certain luminosity in the atmosphere. There were a great many people in the streets, but when they turned into the Park itself, they found it almost deserted--at all events, in the vicinity of the Achilles Statue. "I wonder that the man appointed a meeting with Vass in so public a place," whispered Darrel to Torry, as they took up their position in the blackness under the trees. "The more public the place, the safer it is," replied Torry oracularly. "Hush, there is Vass." In the luminous light the four watchers could see the tall, thin form of the secretary. He walked to and fro, and circulated round the statue in a deliberate manner. Several people entered the gates and passed down the Row, others walked in the direction of the Marble Arch, still the man who had made this appointment did not come. Vass looked at the dial of his watch by the glow of his cigarette, and as he did so the bell of a near church chimed eleven. At once Vass stepped back, and walked up to a point near the watchers, where they could overhear the conversation which was likely to take place, and seize the stranger promptly.