"Of course I'll serve out the trick," he said. "But I didn't suppose I'd ever have a chance to serve another. A mistake like that deserves the severest punishment you can inflict." "You mean you think Nevins left the order on the hook and that you overlooked it?" "Certainly," said the boy. "How else could it have happened?" "I don't know. But neither can I understand how you could have overlooked it if you were at all careful. There are only three others on the hook." "I wasn't as careful as I should have been," said Allan in a low voice, "that's certain." He was sure that he, and he only, had been at fault. Any other explanation seemed ridiculous. "Did Nevins say anything about this train when you came on duty?" pursued the trainmaster. Allan made a mighty effort at recollection. "No," he said, at last; "I'm sure he didn't. We talked a moment about the special, and he spoke of the heavy day's work he'd had. That was all. If he'd said he had an order for it, I certainly shouldn't have forgotten it right away." "Then Nevins broke the rules, too," said Mr. Schofield, and got out his book of rules. "The second paragraph on page seventy-six reads as follows: 'When both day and night operators are employed, one must not leave his post until relieved by the other, and the one going off duty must inform the one coming on respecting unfinished business and the position of trains.'" "He waited until I had looked over the orders," said Allan, with a lively remembrance of Nevins's attitude toward that particular rule. "He supposed that I could read, and if there was anything I didn't understand I'd have asked him." Mr. Schofield put his book back into his pocket, and got out another cigar. His nerves were jangling badly, and he felt the need of something to quiet them. "Well," he said, at last, "I'm sorry." And Allan bowed his head. He accepted the sentence of dismissal which the words implied; it was just. He saw all the air-castles which he had builded so hopefully come tumbling about him; he was overwhelmed in the ruins. He realized that there was no future for him in railroading; no place at the top. He had forfeited his right to serve the road, to expect promotion, by that one mistake, that one piece of carelessness. At least, he told himself, it had taught him a lesson, and one that he would never forget. It had taught him-- [Illustration: "IN THE NEXT INSTANT THE TALL FIGURE HAD BEEN FLUNG VIOLENTLY INTO THE ROOM."] Some one stumbled heavily up the steps to the door, and Mr. Schofield uttered a sharp exclamation of astonishment. Allan started around to see upon the threshold the strangest apparition his eyes had ever rested on.