Dr. Frye, the _X-87's_ surgeon--a weazened little fellow with a grim, saturnine face and scraggly iron-gray hair--had joined us. He answered me. "Set Mokk, he calls himself." "Going to the Moon, for what?" I persisted. Dr. Frye shrugged. "Passengers aren't required to give their family history. Set Mokk is a wealthy man in Ferrok-Shahn, I understand. An enthusiastic Interplanetary traveler--" Len, the young helio operator, diverted my attention. "Have a look," he murmured. "There comes Nina Blake. If she isn't a little beauty I'm a sub-cellar track-sweeper." Now I'm not much for girls, but I don't mind stating thus publicly that Nina Blake struck me then as the most strikingly beautiful girl of any world whom I had ever seen. As she came past, I saw that four stalwart attendants of the _X-87_ were carrying a long oblong box; one of her pieces of luggage. Quite obviously she was particularly concerned over it; she followed it closely, and signaled the men to precede her with it up the incline. I got away from Len Smith and Dr. Frye and was up the incline close after Nina Blake. I saw the squat, square-rigged figure of Capt. Mackensie come forward to greet the girl, his most distinguished passenger. Instantly she spoke to the men carrying the oblong box, and they set it on end beside her on the desk; and at her gesture, they moved away. * * * * * Nobody noticed me as I got up to that box and stood in its shadow. I had no particular motive, save perhaps my instinct as an S.S. Man to probe anything that puzzles me. And suddenly I heard Nina say softly: "No. I'm not--too frightened, Captain. I'll be quite all right." That stiffened me. But a far greater shock came almost instantly afterward. The girl was whispering now to Mackensie, their voices too low for me to hear. She was leaning partly against the upright box, and I saw her slim white hand furtively roving it, one of her fingers pressing what might have been a hidden lever. The sleek, polished side of the box was close to my head--and abruptly, from within it, I seemed to hear a faint muffled, ticking sound! A mechanism in the huge box which the girl's furtive hand had started! It was a slow, rhythmic tick, and a faint swishing. "Oh, you, Penelle. Come here--I want you to meet Miss Blake." Captain Mackensie had noticed me, and his gesture brought me to join them. For a moment we stood in a group as I was introduced. Nina's hand had darted to the box again, perhaps to stop the ticking. "Your first flight, Penelle?" Mackensie was saying. His voice was booming, hearty, loud enough to carry to any of the passengers and crew who were near us here on the dim side-deck. Jamison had told me that of everyone on the _X-87_, only Captain Mackensie would be aware of my true identity and purpose. I caught his significant glance now as he shot it at me from under his heavy gray-black brows. And then abruptly he stepped nearer to me.