"That sounds like honest penitence, and I can forgive you--now. But I shall never be able to forget the afternoon your letter came with its calm announcement that you had been in the room to see about the damaged window; yes, and would probably have to go again. "That letter reached Stockbridge at ten o'clock in the morning of Thursday, the twenty-first. Fifteen minutes later an express train left for New York, and Chalmers and I were the passengers on it, leaving Hilda to follow with the nurse and the baby. At the first opportunity I sent you a telegram. Did you receive it?" My thoughts went back to the yellow telegraphic sheet clutched in John Thaneford's black-knuckled hands, and held up before my helpless eyes. "Yes, it came," I answered slowly, "but too late to be of any use." "I was afraid of that," said Betty, "but we were leaving no stone unturned. We were missing connections all the way down, and I knew that the trap was ready for springing. And someone else knew it, too--John Thaneford." "But," I objected, "Eunice expressly says that John Thaneford did not know the secret; except perhaps in part." "What did he mean then by stupefying you with whiskey, and placing you, bound and helpless, in the big swivel-chair?" put in Warriner. I was silent. "Finally," continued Warriner, "it seemed certain that something had gone wrong with the working of the machinery, whatever it was. Whereupon he started for you--you remember--with bare hands." Ah, yes, I remembered. "Unquestionably, Thaneford was carrying out a perfectly definite plan of procedure. He knew what ought to have happened." "But it didn't happen," I protested. "I'm here and very much alive." "It did, and it didn't," retorted Warriner. "John Thaneford is dead." "You mean--you mean----" I boggled. "Yes, the Terror had entered the room; don't you recall how close I kept to the wall when I was trying to reach you? But it had become a blind Terror, and John Thaneford got in its way." "But how and why?" I asked helplessly. "Betty, it's your turn again," said Warriner, settling back in his chair. Chapter XXI _A Lost Clue_ "Suppose we admit, for the sake of argument," began Betty "that John Thaneford was in possession of the secret. Then everything points back to his father, old Fielding, who certainly had all the brains of the family. Last and most important, it was a secret which Mr. Thaneford, senior, desired to impart to me; he did tell me all he could." "The series of numbers, you mean? I recall them perfectly: 1-4-2-4-8. And what then?" "Do you remember the story of Christian and his fellow pilgrim, Hopeful, imprisoned in Giant Despair's stronghold of Doubting Castle? After languishing for a week or more in darkness and misery, Hopeful suddenly bethinks him of a key which he has in his bosom, a key that will unlock any door in the castle. The rest is easy. "So, too, I had my key, but I had only used it once--to unlock the first and most obvious door----"