One afternoon, at half-past two, Kennedy, who was at the Central Hotel, called at Ella's lodgings and explained how he had seen her father walking in the street with Cole. "I afterwards followed them," he added, "and eventually found that your father is at the Grand Hotel." "Then mischief is certainly intended," declared the girl, her cheeks turning pale. "No doubt. They mean to execute the plot without any further delay. That's my opinion. It will require all our watchfulness and resource if we are to be successful." "Why not warn the police?" suggested the girl. "And, by doing so, you would most certainly send your father to a long term of penal servitude," was her lover's reply. "No. We must prevent it, and for your own sake allow your father a loophole for escape, though he certainly deserves none." Ella had once travelled in the same train as the woman Dexter, but the latter had not recognised her; nevertheless, from inquiries Kennedy had made in London, it seemed that a month before the woman had been living in London, and was a close friend of Cole's. She had only recently gone north to work on munitions, and had, like Ella, been instructed in the working of the electrical cranes. For three days Theodore Drost remained at the Grand Hotel, where he had several interviews with the electrician Cole, and while Ella kept out of the way by day and went to the works at night, her lover very cleverly managed to maintain a strict watch. More than once Ella had contrived to pass the door of the great power-station with its humming dynamos which gave movement to that huge mass of machinery in the three factories turning out munitions, and had seen the man Cole in his blue dungarees busily oiling the machinery. Once she had watched him using thick machine-oil from cans exactly similar to those she had seen stored beneath the table in her father's laboratory. Night after night Ella, working there aloft in her crane, waited and wondered. Indeed, she never knew from hour to hour whether the carefully laid plans of the conspirators might not result in some disastrous explosion, in which she herself might be a victim. But Kennedy reassured her that he was keeping an ever-watchful vigil, and she trusted him implicitly. As a matter of fact, one of the London detectives watching the place was a friend of his, and, without telling him the exact object of his visit, he was able to gain entrance to the works. Naturally the detective became curious, but Kennedy, who usually wore an old tweed suit and a seedy cap, promised to reveal all to him afterwards. About half-past one, on a wet morning, Ella had just stopped her crane when, at the entrance end of the building, she caught a glimpse of some one beckoning to her. It was her well-beloved. In a few moments she had clambered down, and, hurrying through the factory, joined him outside.