They had all but left the hills, and were approaching the level prairie. That they might see the better the flaps had been rolled up, and the soft dry air came freely through the open sides. The mules were straining over the last hill. On either side only a few of the buttes were still visible. They stood out in the moonlight as cleanly cut as the bows of great battleships. The trail at last was level. Mrs. Truesdall's eyes closed. Her head fell forward. But Miss Post, weary as she was in body, could not sleep. To her the night-ride was full of strange and wonderful mysteries. Gratefully she drank in the dry scent of the prairie-grass, and, holding by the frame of the window, leaned far out over the wheel. As she did so, a man sprang into the trail from behind a wall of rock, and shouted hoarsely. He was covered to his knees with a black mantle. His face was hidden by a blood-red mask. “Throw up your hands!” he commanded. There was a sharp creaking as the brakes locked, and from the driver's seat an amazed oath. The stage stopped with a violent jerk, and Mrs. Truesdall pitched gently forward toward her niece. “I really believe I was asleep, Helen,” she murmured. “What are we waiting for?” “I think we are held up,” said Miss Post. The stage had halted beyond the wall of rock, and Miss Post looked behind it, but no other men were visible, only a horse with his bridle drawn around a stone. The man in the mask advanced upon the stage, holding a weapon at arm's-length. In the moonlight it flashed and glittered evilly. The man was but a few feet from Miss Post, and the light fell full upon her. Of him she could see only two black eyes that flashed as evilly as his weapon. For a period of suspense, which seemed cruelly prolonged, the man stood motionless, then he lowered his weapon. When he opened his lips the mask stuck to them, and his words came from behind it, broken and smothered. “Sorry to trouble you, miss,” the mask said, “but I want that man beside you to get out.” Miss Post turned to the travelling salesman. “He wants you to get out,” she said. “Wants me!” exclaimed the drummer. “I'm not armed, you know.” In a louder voice he protested, faintly: “I say, I'm not armed.” “Come out!” demanded the mask. The drummer precipitated himself violently over the knees of the ladies into the road below, and held his hands high above him. “I'm not armed,” he said; “indeed I'm not.” “Stand over there, with your back to that rock,” the mask ordered. For a moment the road agent regarded him darkly, pointing his weapon meditatively at different parts of the salesman's person. He suggested a butcher designating certain choice cuts. The drummer's muscles jerked under the torture as though his anatomy were being prodded with an awl. “I want your watch,” said the mask. The drummer reached eagerly for his waistcoat.