An icy waste was beneath them, where the sub-polar regions were wrapped in the mantle of their endless winter. Here ships never passed. Northward, toward the Pole, were liner lanes in the higher levels, but here was a deserted sector. And here Walter Harkness had elected to carry on his experiments. A rise of land showed gaunt and black, and the pilot was guiding the ship in a long slant upon it. He landed softly beside a building in a sheltered, snow-filled valley. Harkness shivered as he stepped from the warmth of their insulated cabin, and he fumbled with shaking fingers to touch the combination upon the locked door. It swung open, to close behind the men as they stood in the warm, brightly-lighted room. Nitro illuminators were hung from the ceiling, their diffused brilliance shining down to reflect in sparkling curves and ribbons of light from a silvery shape. It stood upon the floor, a metal cylinder a hundred feet in length, whose blunt ends showed dark openings of gaping ports. There were other open ports above and below and in regular spacing about the rounded sides. No helicopters swung their blades above; there were only the bulge of a conning tower and the heavy inset glasses of the lookouts. Nor were there wings of any kind. It might have been a projectile for some mammoth gun. Harkness stood in silence before it, until he turned to smile at the still-wondering pilot. "Chet," he said, "it's about finished and ready--just in time. We've built it, you and I; freighted in the parts ourselves and assembled every piece. We've even built the shop: lucky the big steeloid plates are so easily handled. And you and I are the only ones that know. "Every ship in the airlanes of the world is driven by detonite--and we have evolved a super-detonite. We have proved that it will work. It will carry us beyond the pull of gravitation; it will give us the freedom of outer space. It is ours and ours alone." "No," the other corrected slowly, "it is yours. You have paid the bills and you have paid me. Paid me well." "I'm paying no more," Harkness told him. "I'm broke, right this minute. I haven't a dollar--and yet I say now that poor Warrington was right: this is my lucky day." * * * * * He laughed aloud at the bewilderment on the pilot's face. "Chet," he said slowly, and his voice was pitched to a more serious tone, "out there is a new world, the Dark Moon. 'Tremendous density,' they said. That means it can hold an atmosphere of its own. It means new metals, new wealth. It means a new little world to explore, and it's out there waiting for us. Waiting for us; we will be the first. For here is the ship that will take us. "It isn't mine, Chet; it's ours. And the adventure is ours; yours and mine, both. We only meant to go a few hundred miles at first, but here's something big. We may never come back--it's a long chance that we're taking--but you're in on it, if you want to go...."