The spy, knowing himself discovered, had abandoned his own car in favour of a passing taxicab, and in the latter had taken up the pursuit. Paul Harley lighted a cigarette. Oddly enough, he was aware of a feeling of great relief. In the first place, his sixth sense had been triumphantly vindicated; and, in the second place, his hitherto shadowy enemies, with their seemingly supernatural methods, had been unmasked. At least they were human, almost incredibly clever, but of no more than ordinary flesh and blood. The contest had developed into open warfare. Harley’s accurate knowledge of London had enabled him to locate No. 236 South Lambeth Road without recourse to a guide, and now, walking on past the big gas works and the railway station, he turned under the dark arches and pressed on to where a row of unprepossessing dwellings extended in uniform ugliness from a partly demolished building to a patch of waste ground. That the house was being watched he did not doubt. In fact, he no longer believed subterfuge to be of any avail. He was dealing with dangerously accomplished criminals. How clever they were he had yet to learn; and it was only his keen intuitive which at this juncture enabled him to score a point over his cunning opponents. He walked quite openly up the dilapidated steps to the door of No. 236, and was about to seize the dirty iron knocker when the door opened suddenly and a girl came out. She was dressed neatly and wore a pseudo fashionable hat from which a heavy figured veil depended so as almost to hide her features. She was carrying a bulging cane grip secured by a brown leather strap. Seeing Harley on the step, she paused for a moment, then, recovering herself: “Ellen!” she shouted down the dim passageway revealed by the opening of the door. “Somebody to see you.” Leaving the door open, she hurried past the visitor with averted face. It was well done, and, thus disguised by the thick veil, another man than Paul Harley might have failed to recognize one of whom he had never had more than an imperfect glimpse. But if Paul Harley’s memory did not avail him greatly, his unerring instinct never failed. He grasped the girl’s arm. “One moment, Miss Jones,” he said, quietly, “it is you I am here to see!” The girl turned angrily, snatching her arm from his grasp. “You’ve made a mistake, haven’t you?” she cried, furiously. “I don’t know you and I don’t want to!” “Be good enough to step inside again. Don’t make a scene. If you behave yourself, you have nothing to fear. But I want to talk to you.” He extended his arm to detain her. But she thrust it aside. “My boy’s waiting round the corner!” she said, viciously. “Just see what he’ll do when I tell him!” “Step inside,” repeated Harley, quietly. “Or accompany me to Kennington Lane Police Station--whichever you think would be the more amusing.” “What d’you mean!” blustered the girl. “You can’t kid me. I haven’t done anything.”