A hansom cab which had passed swiftly the one Señor Guffanta was in, a cab in which was seated a young man with a brown moustache, and on the roof of which was a portmanteau and a bundle of rugs. "Quick!" the Señor said, speaking for the first time almost incoherent English; "follow that cab with the valise on the top. Quick, I say! I will pay you anything!" "How can I be quick!" the man said with an oath, "when I can hardly turn my cab round? Which is the one you mean?" "The one with the valise, I say, that passed just now. I will give you everything I have in my pockets if you catch it." But it was no use. Before the cab could be turned and put in pursuit, the other one had disappeared round a corner into a short street, from which, ere Señor Guffanta's cab had reached it, it had again disappeared. "Blood of my father!" the Señor said to himself in Spanish, "am I never to seize him?" Then he once more altered his directions to the cabman, and bade him drive to Occleve House. He walked into the room in which he heard that Lord Penlyn and Mr. Stuart were seated, and the excitement visible upon his face told them that something had happened. "I have seen him," he said, going through no formality of greeting; he was far too disturbed for that. "I have seen him once again, and once again I have lost him." "Where have you seen him?" Stuart asked. "Not at Occleve Chase, surely!" Penlyn exclaimed. "No--here, in London! Not half-an-hour ago, in a cab. And I have missed him! He went too swiftly, and I lost sight of him." "What will you do?" they both exclaimed. "At present I do not know. I feel as though I shall go mad!" Then a moment after he said: "Give me the keys of the garden; at once, give them to me." Penlyn took them from a drawer and gave them to Señor Guffanta, and he, bidding the others remain where they were, opened the door leading into the garden from the back of the house, and went out into it. It was but a few minutes before he returned, but when he did so the bronze had left his face and he was deathly pale. "Lord Penlyn," he said, biting his lips as he spoke, and clenching his hands until the nails penetrated the palms, "to whom have you given those keys during my absence?" "To no one," Penlyn answered. "I promised you I would not let any one have them." "You have given them to no one?" Guffanta said, while his eyes shone fiercely as he looked at the other. "To no one! To no one! Then will you tell me how the murderer of Walter Cundall has been in that garden within the last few hours?" CHAPTER XVIII.