Rex tried to fathom Barzoo's words. Familiar with languages and dialects the System over, he got some of Barzoo's meaning. The Martian leader was worried about the condition in which the hutch floor had been left. Perhaps the wall-section had been left tilted. After a while, the other Martian got to his feet and trotted back through the darkness along the tunnel through which they had come. * * * * * After the Martian left, Barzoo wiped his mouth with the back of his hand and motioned Rex and Jean to get up and move into a passage to their right. "How much further can he take us?" Jean asked. "After the first drop back at the hutch, it seems to me the tunnel has been level." "A floor can be deceptive. We could have been moving down a gradual slope for miles." Jean said nothing. The going was easier now, this tunnel being lighted at intervals by the strange overhead bulbs. Rex asked, "Are you sore at me for what happened back at the farm? For not telling you the truth?" "No. We're in too much trouble to waste time being angry. What's done is done. Only the future is important now." Rex could have made his self-recrimination vocal but he felt that too would be a waste of time. He said, "Didn't anybody--any of you Terrans know about the opening in that hutch?" "I'm sure no one did--except perhaps Tommy." She thought that over and added, "No--that's absurd. If Tommy had known it he wouldn't have been able to keep it to himself." "Maybe they'll hunt around and find it." "Maybe--but I hope they don't." "Why not?" "If they find the opening they'll come looking for us. These Martians are hostile. Some of our men might be killed and they have wives and families." Jean made Rex feel ashamed of himself. "Don't worry. I'll get you out of here." She glanced up at him. Her chin trembled slightly as she sought to stiffen it. At that moment they walked into a larger tunnel. There were more overhead bulbs here and a ribbon of narrow-gauge track stretching off into the distance. "A railroad!" Rex exclaimed. "I wonder where it goes?" "I've got a hunch we're going to find out." One of the Martians had gone around a shoulder of the tunnel. There was a whining sound. He returned in the driver's seat of a small rail car. Barzoo motioned the Terrans into one of the seats. The other Martians got in behind them. The driver pulled a throttle. The whining sound increased and the car moved off down the tracks. Rex listened for a time, inspected the portion of the car within range of his eyes, then said, "I wonder what kind of power this thing uses?" Jean did not answer. Her head had dropped to his shoulder. She was asleep. He settled himself, forming a pocket with his body so she could rest against him with the seat supporting her. Behind him the eyes of the three Martians, including Barzoo, had also closed. Rex wondered if the driver was asleep also.