We calculated that, finding he had been debited with three copies of the "plans," whereas he actually received four, Easterbrook would calmly pocket one of them and return to the proper department the three for which he had signed. Events proved that we were right. In the afternoon, at the usual time, he left the office. Three minutes later we ascertained that the fourth copy of the "plans" was not in his desk. He had taken it with him, and it was easy to guess his purpose. From that moment his doom was sealed. We could have arrested him at once, of course, but we wanted to know by what means those plans were to be dispatched to Germany. If we could only find that out one finger of the Hidden Hand would assuredly be lopped off for good. On leaving the office Easterbrook made for a public telephone office, where, as it happened, three boxes stood side by side. As he entered the one, an agent of the Special Branch entered the one farthest from him. The boxes were of the threepence-in-the-slot pattern, and the trifling delay caused by dropping in the three pennies gave the detective his opportunity. Ringing up the operator at the Exchange, he demanded, in the name of the police, that Easterbrook's conversation should be "tapped." The operator promptly "plugged" him on to the line Easterbrook was using, so that he was able to listen, quite unknown to Easterbrook, to the conversation which followed. "Is that 7257 North?" Easterbrook began. "I want to speak to Mr Huggon-Rose," he went on. "That you, Rose? This is Easterbrook. Will you come down to Piccadilly and have some dinner with me? I am just arranging a yachting trip, and perhaps you would like to make one of the party. All right. Be at Scott's at seven o'clock. Good-bye." And he rang off. Seven o'clock found Easterbrook and Huggon-Rose dining comfortably at Scott's. Four men of the Special Branch, immaculately attired and apparently mere men-about-town, were seated at different tables near them. Easterbrook and his guest talked yachting ostentatiously, and many maps and papers were handed backward and forward. _One_ of these, the lynx-eyed watchers noted, passed from Easterbrook to Huggon-Rose _and was not returned_. It was the confidential paper! Another link in our chain had been forged! At half-past ten the two conspirators rose to leave. At the door of the restaurant they brushed past a man in seafaring dress, quite obviously a Dutch sailor, and, swiftly though it was done, one of our watchers saw a folded paper slip from Huggon-Rose's hand into that of the Dutchman. He made off at once, closely shadowed by two of our men, while Easterbrook and Huggon-Rose walked away together, evidently looking for a taxicab, none too numerous at that hour.