The vehicles of the Space Men were even greater puzzles. How did they fly out here where the rocket was the only human invention that could move? Many of the vehicles were visible now through the flier's windows. They were disc shaped platforms of a strange lusterless metal. In the center of the top was an opening in which the Space Men sat. Projecting from the discs were a series of levers, permitting evidently simple control. But no hint of their principle of operation was given. They emitted no rocket jets; no beams projected from them. Austin realized that there were many mysteries of the universe with which he was not acquainted; this was certainly one. * * * * * The sound of bodies moving about on the outer shell of the flier was still audible. Presently there was a sharp explosion somewhere toward the stern. The rockets immediately fell silent. The fugitives saw that some of the Space Men were now busying themselves with long metal cables. Deftly and expertly they were looping them through the eyelet rings set at frequent intervals along the sides of the flier. The other ends of the cables they fastened firmly to similar rings on their vehicles. They finished the job with all the efficiency of trained military engineers. Then, with the small interplanetary vessel in tow, the Space Men began to move off toward Mars, rapidly gaining momentum until their speed must have considerably exceeded that which most space craft could equal. They deflected their course somewhat from the direct path to the Red Planet, probably to avoid a meeting with any wandering ship. Throughout the fantastic voyage Shelby and Janice Darell found little to do but stare dumbfounded at their weird captors and to watch the rapidly dropping needle of their oxygen supply-gauge. But as it proved, there was little danger of suffocation, for the Space Men were making good time. And so, after two hours of flying they came to Mars--not to Taboor which the fugitives had previously hoped to reach, but to a deep valley in the desert of the Taraal. The strange caravan circled around to the night side of the planet, and then, slowly and carefully, but with a hint that they understood their work well, they proceeded to lower the disabled craft through the atmosphere to the ground below. The door of the flier was torn open like a paper thing, and a black giant fully as huge and burly as Alkebar himself hustled the adventurers roughly out into the open. The pock-marked face of Loo, the Martian name for their nearer moon, was in the sky, and by its light they could see hundreds of Space Men crowding about them. Plainly this Martian colony was fairly well peopled, for there were many more than the five hundred who captured them. The attitude of the onlookers was one of casual curiosity. For the moment at least they were not showing the more brutal side of their characters.