At nine o'clock on the following evening Ella Drost descended in the lift from the second floor of the Victoria Hotel, in Sheffield, and, wearing her blanket-coat, went to the station platform and bought a ticket to Chesterfield--the town with the crooked spire. Half-an-hour later she walked out into the station yard where she found her lover, the good-looking Flight-Commander, awaiting her in a big grey car. He no longer wore uniform, but was in blue serge with a thick brown overcoat. "By Jove, Ella!" he exclaimed in welcome, as he grasped her hand. "I'm jolly glad you've come up here! There's a lot going on. You were perfectly correct when you first hinted at it. I've been watching patiently for the past month. Hop in; we've no time to lose." Next second, Ella was in the seat beside her lover, and the powerful car moved off down the Arkwright Road, a high-road running due eastward, till they joined another well-kept highway which, in the pale light, showed wide and open with its many lines of telegraphs--the road to Clowne. On through the falling darkness they travelled through Elmton and up the hill to Bolsover, where they suddenly turned off to the left and, passing down some dark, narrow lanes, with which Kennedy was evidently familiar, they at last pulled up at the corner of a thick wood. "Now," he said, speaking almost for the first time, and in a low voice, "we'll have to be very careful indeed." He had shut off his engine and switched off his lamps. "We ought to make quite certain to-night that we are not mistaken," she said. "That is my intention," was her lover's reply, and then she flung off her coat and crossed the stile, entering the wood after him. He had a pocket flash-lamp, and ever and anon threw its rays directly upon the ground so that they could see the path. The latter was an intricate one, for twice they came to cross-paths, and in both cases Kennedy selected one without hesitation. At last, however, they began to move down the hill more cautiously, conversing in low whispers, and showing no light until they at last found themselves in the grounds attached to a large, low-built country house, lying in the valley. "Ortmann is living here as Mr Horton," Kennedy whispered. "They told me in the village that he took the house furnished about three months ago, from a Major Jackson, who is at the front." "But why is he living down here--in a house like this?" she asked. "That's just what we want to discover. Many Germans have country houses in England for some mysterious and unknown reason." Kennedy, glancing at his luminous wrist-watch, noted that it was nearly two o'clock in the morning. From where they stood at the edge of the wood the house was plainly visible, silhouetted on the other side of a wide lawn. No light showed in any of the windows, and to all appearances the inmates were asleep.