We could not think why we should be wanted. It was the darkness of mid-evening when we left the Planetara for Halsey's office. It was not a long trip. We went direct in the upper monorail, descending into the subterranean city at Park-Circle 30. * * * * * We had never been to Halsey's office before. We found it to be a gloomy, vaultlike place in one of the deepest corridors. The door lifted. "Gregg Haljan and Daniel Dean." The guard stood aside. "Come in." I own that my heart was unduly thumping as we entered. The door dropped behind us. It was a small blue-lit apartment--a steel-lined room like a vault. Colonel Halsey sat at his desk. And the big, heavy-set, florid Captain Carter--our commander of the Planetara--was here. That surprised us: we had not seen him leave the ship. Halsey smiled at us gravely. Captain Carter said, "Sit down, lads." We took the seats. There was an alarming solemnity about this. If I had been guilty of anything that I could think of, it would have been frightening. But Halsey's first words reassured me. "It's about the Grantline Moon Expedition. In spite of our secrecy, the news has gotten out. We want to know how. Can you tell us?" Captain Carter's huge bulk--he was about as tall as I am--towered over us as we sat before Halsey's desk. "If you lads have told anyone--said anything--let slip the slightest hint about it--" Snap smiled with relief; but he turned solemn at once. "I haven't. Not a word!" "Nor have I," I declared. * * * * * The Grantline Moon Expedition! We had not thought of that as a reason for this summons. Johnny Grantline was a close friend to us both. He had organized an exploring expedition to the Moon. Uninhabited, with its bleak, forbidding, airless, waterless surface, the Moon--even though so close to the Earth--was seldom visited. No regular ship ever stopped there. A few exploring parties of recent years had come to grief. But there was a persistent rumor that upon the Moon, mineral riches of fabulous wealth were awaiting discovery. The thing had already caused some interplanetary complications. The aggressive Martians would be only too glad to explore the Moon. But the U.S.W.[2] definitely warned them away. The Moon was World Territory, we announced, and we would protect it as such. The threatened conflict between the Earth and Mars had come to nothing. There was, this year of 2079, a thorough amity between all three of the inhabited planets. It still holds, and I pray that it may always hold. There was, nevertheless, a realization by our government, that whatever riches might be upon the Moon should be seized at once and held by some reputable Earth Company. And when Johnny Grantline applied, with his father's wealth and his own scientific record of attainment, the government was only too glad to grant him its writ. * * * * *