It was a statement which should have been startling, but Burke nodded. Sandy went on, carefully, "That cube about a supply-officer's duties was pretty explicit. Things were getting difficult." Burke did not seem to hear. They went on and on. They came to the place where Keller had turned aside. Burke silently indicated the turning. They moved along this other gallery. "Joe," said Sandy pleadingly. "Is it really so bad?" "Strictly speaking, I don't see a chance. But that's just the way it looks now. There must be something that can be done. The trick is to find it. Meantime, why panic?" "You--act queer," protested Sandy. "I feel queer," he said. "I know various ways to approach problems. None of them apply to this one. You see, it isn't really our problem. We're innocent bystanders, without information about the situation that apparently will kill us and everybody back on Earth. If we knew more about the situation, we might find some part of it that could be tackled, changed. There may be something in this case--perhaps a message left by the garrison for the people who sent them here. I can't see why it'd be placed here, though." He slowed, looking down one cross-gallery after another. "Here it is." They'd come to the clumsily-made case with the inscription on it. It was placed against the wall of a corridor, facing the length of another gallery which came from the side at this point. A little distance down the other passage, the line of doors was broken by an archway which gave upon a hewed-out compartment. The opening was wide enough to show a fragment of a metal floor. There was no sign of any contents. Other compartments nearby were empty. The placing of the inscribed box was inexplicable. But the inscription was sharply clear. "Maybe," suggested Sandy forlornly, "it says something like 'Explosives! Danger!'" "Not likely," said Burke. He'd examined the box before. He'd brought along a tool suited to the job of opening it. He set to work, then stopped. "Sandy," he said abruptly, "I think the gravity-generator's a couple of corridors in that direction. Will you look and see if there are any tools there that might be better than this? Just look for a place where tools might be stored. If you find something, call me." She went obediently down the lighted, excavated corridor. She reached the vast cavern. Here there were myriad tube-lights glowing in the ceiling--and the gravity machine. It was gigantic. It was six storeys high and completely mysterious. She looked with careful intentness for a place where tools might have been kept by the machine's attendants.