"You had not the advantage of knowing my father, Mr. Alder," he said coldly. "I was only a boy when he left us, but I shall always look upon him as my ideal man. His only fault was that he was too sensitive and too unselfish. That any one should lose money through him would cut him to the heart. His sense of honour was most acute, any theory of his disappearance which conflicts with that is a mistaken one." It pleased me to hear the lad speak out so roundly, and yet I knew that the facts were against him, and that he was incapable of taking an unprejudiced view of the situation. "I only speak as an outsider," said I. "And now I must leave you, for I have a long walk before me. Your story has interested me so much that I should be glad if you could let me know the sequel." "Leave me your card," said he; and so, having bade him "good-night," I left him. I heard nothing more of the matter for some time, and had almost feared that it would prove to be one of those fleeting experiences which drift away from our direct observation and end only in a hope or a suspicion. One afternoon, however, a card bearing the name of Mr. J. H. Perceval was brought up to my office in Abchurch Lane, and its bearer, a small, dry, bright-eyed fellow of fifty, was ushered in by the clerk. "I believe, sir," said he, "that my name has been mentioned to you by my young friend, Mr. Felix Stanniford?" "Of course," I answered, "I remember." "He spoke to you, I understand, about the circumstances in connection with the disappearance of my former employer, Mr. Stanislaus Stanniford, and the existence of a sealed room in his former residence." "He did." "And you expressed an interest in the matter." "It interested me extremely." "You are aware that we hold Mr. Stanniford's permission to open the door on the twenty-first birthday of his son?" "I remember." "The twenty-first birthday is to-day." "Have you opened it?" I asked eagerly. "Not yet, sir," said he gravely. "I have reason to believe that it would be well to have witnesses present when that door is opened. You are a lawyer, and you are acquainted with the facts. Will you be present on the occasion?" "Most certainly." "You are employed during the day, and so am I. Shall we meet at nine o'clock at the house?" "I will come with pleasure." "Then you will find us waiting for you. Good-bye, for the present." He bowed solemnly, and took his leave. I kept my appointment that evening, with a brain which was weary with fruitless attempts to think out some plausible explanation of the mystery which we were about to solve. Mr. Perceval and my young acquaintance were waiting for me in the little room. I was not surprised to see the young man looking pale and nervous, but I was rather astonished to find the dry little City man in a state of intense, though partially suppressed, excitement. His cheeks were flushed, his hands twitching, and he could not stand still for an instant.