In the matter of food, you had to ration yourself so stringently that you caught yourself looking with longing eyes at the few, weird, bulbous shrubs and the scattered lichens, which were the only vegetation on this dying world. Only you knew that these arid growths would never be good to eat. Those long Ionian days passed. One after another. Five, ten, fifteen. Harwich knew he was losing strength slowly. The inevitable was catching up with him. But those hard years in the Interplanetary Patrol Service, and the rigid physical discipline, had made him as tough as steel wire. With the boy, Paul Arnold, it was not the same. He was very young, and not too robust. And he was slipping fast. "What's the matter with me, Evan?" he would grumble. "All this desert isn't real, is it? We're not on the Forbidden Moon, are we? I'm dreaming." "You're just tired out, that's all, fella," Harwich would answer in a tone that he would try to make reassuring. He would put an arm around the kid's shoulders, to support his faltering steps. Big brother stuff.... Paul had plenty of pluck, all right, but there wasn't much else left in him. He was wearing out, mile by mile, staggering under his heavy pack. * * * * * Every resource was reaching its limit, now. Food supplies had dwindled away to nothing, at last. The little atomic motor that worked the air compressor and separator unit, was breaking down. It could hardly pump enough oxygen into the air flasks any more. But there was nothing to do but keep on the march, anyway, in spite of handicaps. Evan Harwich felt as though he was going slowly mad. Brooding thoughts came into his mind constantly. Clara Arnold. Where was she now? What had happened back there on Ganymede? What had George Bayley done? When would he come to Io, with the ship he would surely fit out with a new Penetrator? What was Clara thinking? What if she knew her brother was alive on the Forbidden Moon, but slowly dying? What if Bayley told her that maybe Paul was still alive, adding that he himself was the only person that might be able to effect a rescue? What if he had finally used this means, this possibility, to make Clara marry him? She didn't love Bayley, the fat printer! She couldn't! And he wouldn't even have to promise to attempt a rescue--only suggest that he might try. Clara must be half crazy herself, thinking of her brother. After all she'd lost her father to the Forbidden Moon too.