It was just after leaving Tipton that his familiar knock had called one of them to the door to let him in. Taken completely off their guard, as four men one after the other jumped in among them, the guards had no opportunity to seize their firearms. They had been knocked down on the floor of the car, cloths drugged with some subtle acid had been held over their faces. They knew no more until they had been discovered by the division superintendent. "It's easy to guess it out," whispered Glidden to Ralph while the officials in the room were piecing all these bits of information together. "Yes," responded Ralph, "the conspirators in some way received advance information of every step we intended to make." "They must have got aboard secretly beyond Tipton, or have been hidden in the last milk car," suggested Glidden. "They jumped on and doped the brakeman, disposed of him, later of the two guards, and were in possession. The division superintendent reports that the wires were found cut just out of Tipton. The crowd had planned out everything to a second, with conspirators posted all along the line." "But the missing car," said Ralph thoughtfully; "what has become of it?" Neither he nor Glidden could figure out a solution of this difficult problem. Even the experienced official after a long confab gave it up. The only thing they could do was to order a hasty search for Bob Adair, the road detective, to rush to the spot with all the force he needed. The superintendent spoke pleasantly to Ralph and Glidden as the day force relieved them. He even forgot his anxieties long enough to commend them for the hard work they had done and the close tab they had kept on all the occurrences of the night. "It's a bad mess for the Great Northern," he said with a worried face, "and it proves that our enemies are not as dull as we thought they were." Ralph went home tired out. He found it hard, however, to get to sleep. The strain and excitement of the preceding twelve hours told severely on his nerves. All through the morning his vivid dreams were of snow blockades, cut wires, and stolen treasure cars. On account of their special service on behalf of the pay car affair, Glidden and himself were relieved from duty for twenty-four hours. The old dispatcher dropped in at the Fairbanks home shortly after noon. "Have they found any trace of the missing pay car?" at once inquired Ralph. "Stolen, you mean," corrected Glidden. "No. Theories? Lots of them. She was simply cut off from the train. She couldn't have derailed, for there's no trace of that unless she went up in the air. Of course, whoever manipulated her sent her off on a siding among the mountains on a down grade." "And that is the last known of it. Well, what later?" "Adair will be over to find out soon, or else he won't," retorted Glidden crisply. "You know that web of old abandoned sidings and spurs branching out the other side of Maddox?" "Near Eagle Pass, you mean?"