Air travel is so comfortably regulated at the present day that Robin Greve, looking back at his trip by air from Croydon Aerodrome to the big landing-ground outside Rotterdam, acknowledged that he had more excitement in his efforts to stir into action a lethargic Dutch passport official in London, so as to enable him to catch the air mail, than in the smooth and uneventful voyage across the Channel. He reached Rotterdam on a dull and muggy afternoon and lost no time in depositing his bag at the Grand Hotel. An enquiry at the office there satisfied him that Mary Trevert had not registered her name in the hotel book. Then he set out in a taxi upon a dreary round of the principal hotels. But fate, which loves to make a sport of lovers, played him a scurvy trick. In the course of his search it brought Robin to that very hotel towards which, at the selfsame moment, Mary Trevert was driving from the station. By the time she arrived, Robin was gone and, with despair in his heart, had started on a tour of the second-class hotels, checking them by the Baedeker he had bought in the Strand that morning. It was eight o’clock by the time he had finished. He had drawn a blank. The sight of a huge, plate-glass-fronted café reminded him that in the day’s rush he had omitted to lunch. So he paid off his taxi and dined off succulent Dutch beefsteak, pounded as soft as velvet and swimming with butter and served in a bed of deliciously browned ‘earth apples,’ as the Holländers call potatoes. The café was stiflingly hot; there was a large and noisy orchestra in the front part and a vast billiard-saloon in the back—a place of shaded lights, clicking balls, and guttural exclamations. The heat of the place, the noise and the cries combined with the effect of his long journey in the fresh air to make him very drowsy. When he had finished dinner he was content to postpone his investigations until the morrow and go to bed. Emerging from the café he found to his relief that his hotel was but a few houses away. As he sat at breakfast the next morning, enjoying the admirable Dutch coffee, he reviewed the situation very calmly but very thoroughly. He told himself that he had no indication as to Mary Trevert’s business in Rotterdam save the supposition that she had found the van der Spyck letter and had come to Rotterdam to investigate the matter for herself. He realized that the hypothesis was thin, for, in the first place, Mary could have no inkling as to the hidden significance of the document, and, in the second place, she was undoubtedly under the impression that Hartley Parrish was driven to suicide by his (Robin’s) threats.