Thomas had not long left Walter Brooklyn when Joan arrived to see him. She had come into the police-station alone, leaving Lucas and Ellery outside in the car to wait for her return. While they waited, Ellery told his guardian more about his engagement to Joan, and received from him very hearty congratulations. “You didn’t take my advice, my boy,” Lucas said; “but now that things have come out right, I’m most heartily glad that you didn’t. I have hoped for this for a long time. I’m very fond of you both, and I can see there’s no doubt about your being fond of each other.” Which was very pleasant hearing for Ellery; for he had a great liking for his guardian, and he knew that his friendly countenance would be likely to stand him in good stead with Sir Vernon Brooklyn, of whom he was more than a little afraid. “You must back me up with Sir Vernon,” he said; and Lucas readily promised his help. It was three-quarters of an hour before Joan came out of the police-station. She seemed well satisfied, smiling back at the policeman who accompanied her to the door. “He has told you?” asked Ellery, as he held open the door of the car. “What he had to tell,” Joan replied. “It was not very much; but it makes everything different. Let us go back and talk it over.” Lucas drove straight back to Liskeard House, and there, in Joan’s room, the three held a consultation. “He was not here at all,” she told them. “I mean he did not come back to the house on Tuesday night. The telephone message must be all a mistake.” “Do you mean that he knows nothing at all about it?” asked Ellery. “I am quite sure that he knows nothing. He has told me exactly what he did after leaving here and up to the time when he went back to his Club.” “You may think I ought not to ask this, Joan,” said Lucas; “but are you quite sure of what you say?” “Absolutely sure. He was telling me the truth, I know.” “Then I suppose,” Ellery put in, “we can produce witnesses to prove that he was somewhere else when he was supposed to be here. But who the devil did send that telephone message if he did not?” Lucas put in a word. “Never mind that for the moment. The main thing now is to prove that he did not send it. Who was with him and where was he?” “Ah, that’s just the difficulty. He has told me exactly where he went; but I don’t see how we can find any one to prove it.” “Do you mean that he was alone all the time, and no one saw him?” asked Ellery. “Well, not quite that; but something very like it, I’m afraid.”