"Another one!" she said breathlessly, and pointed where the blackness was looped with writhing fire. It came swiftly near to show the outline of the dread serpent form; the suction cups showed plainly. Danger was in this thing, Harkness knew, but it passed them by before he could move. The further lookout showed two gleaming monsters locked together in deadly embrace. So swift was their whirling motion that details of form were lost: only a confusion of lashing tentacles that whipped and tore, and one glimpse of a savage maw that sheared the tentacles off. Then the serpent was upon them. * * * * * Harkness had seen one time a sight that was indelibly impressed upon his memory. A steeloid cable had broken under a terrific strain; the end of it had lashed out with a speed the eye could not follow, to wind itself around the superstructure of a submarine--and the men who were gathered there. He thought of that now, saw again the bleeding mass that had been an instant before a group of humans, as the serpent seized its prey. The two combatants were encircled in a living coil of light. Then, as motion ceased, the ethereal sea went dark except for pulsing suction cups that drew and strained at the bodies they held. Harkness was groping for the controls--he saw too plainly their own helplessness when they were at rest--but the voice of Dianne checked him. "That bright star went out," she said; and Harkness let his gaze follow where she pointed. The stars that were distant suns shone in brilliant points of light; no atmosphere here to dim them or cause a flickering. A bright point vanished as she looked--another!--and he knew abruptly that he was seeing a circle of blackness that moved slowly between them and the stars. "The Moon!" he shouted. "The Dark Moon!" And now his hand found the controls that threw their ship into thunderous life. It was approaching! He swung the metal ball to throw them ahead and to one side, and the roar from the stern told of the fast-growing speed that was pressing them to the floor.... * * * * * An hour of wild flight, and the circle was close upon them. Too faintly lighted to register in the telescopes of Earth, there was still enough of luminosity to mark it as a round disc of violet that grew dimly bluish-green around the edge. It ceased to grow. Their ship, Harkness knew, was speeding beside it some hundreds of miles away. But they were within its gravitational pull, and were falling toward it. And he aimed his ship bow-on to make the forward blast a check upon their falling speed. The circle broadened; became a sphere; and then they were plunging through clouds more tenuous than any vapors of Earth--thick layers of gas that reflected no rays from the distant sun.