"Grab hold!" Shann was giving the orders now. "By the look of that opening we had better try crawling. I've a torch on at low----" "Good enough." The other's fingers fumbled on the band about Shann's slim waist until they gripped tight at his back. He started on into the opening, drawing Thorvald by that hold with him. Luckily, they did not have to crawl far, for shortly past the entrance the fault or vein they were following became a passage high enough for even the tall Thorvald to travel without stooping. And then only a little later he released his hold on Shann, reporting he could now see well enough to manage on his own. The torch beam caught on a wall and awoke from there a glitter which hurt their eyes--a green-gold cluster of crystals. Several feet on, there was another flash of embedded crystals. Those might promise priceless wealth, but neither Terran paused to examine them more closely or touch their surfaces. From time to time Shann whistled. And always he was answered by the wolverines, their calls coming from ahead. So the men continued to hope that they were not walking into a trap from which the Throgs could extract them. "Snap off your torch a moment!" Thorvald ordered. Shann obeyed. The subdued light vanished. Yet there was still light to be seen--ahead and above. "Front door," Thorvald observed. "How do we get up?" The torch showed them that, a narrow ladder of ledges branching off when the passage they followed took a turn to the left and east. Afterward Shann remembered that climb with wonder that they had actually made it, though their advance had been slow, passing the torch from one to another to make sure of their footing. Shann was top man when a last spurt of effort enabled him to draw himself out into the open, his hands raw, his nails broken and torn. He sat there, stupefied with his own weariness, to stare about. Thorvald called impatiently, and Shann reached for the torch to hold it for the officer. Then Thorvald crawled out; he, too, looked around in dull surprise. On either side, peaks cut high into the amber of the sky. But this bowl in which the men had found refuge was rich in growing things. Though the trees were stunted, the grass grew almost as high here as it did on the meadows of the lowlands. Quartering the pocket valley, galloped the wolverines, expressing in that wild activity their delight in this freedom. "Good campsite." Thorvald shook his head. "We can't stay here." And, to underline that gloomy prophesy, there issued from that hole through which they had just come, muffled and broken, but still threatening, the howl of the Throgs' hound. The Survey officer caught the torch from Shann's hold and knelt to flash it into the interior of the passage. As the beam slowly circled that opening, he held out his other arm, measuring the size of the aperture.