"The scientists must not awaken until we have the robots under our command. By giving each scientist a heavy dose of Vanadol, enough for weeks of sleep, we circumvent the antidote for sleep-freeze. It's this way: when we land, the mechanism within each robot timed for release on arrival, activates them for their one and only task, the administration of anti-sleep freeze, but since each scientist will have been thoroughly drugged with Vanadol, they'll be released from sleep-freeze, but will continue to sleep under the powerful narcotic. The robots then will be given such commands as we decide on, and will be entirely answerable to us three only. They will facilitate immensely the task of making Europa truly habitable, and since they are almost indestructible, will be the most valuable of all weapons. Let's get busy, if there's enough Vanadol, we've won the first round after all!" Presently the Martian returned, "There's tons of the stuff," he announced. Mark had to explain all over again. VI "Panadur!" Mark Lynn breathed softly as he glanced at the stark grandeur of Europa from one of the glassite ports. It was night. The macabre glow of Jupiter's Red Spot enveloped the satellite in a red opaline haze that made the vari-colored cliffs gleam with twisted flames in deep crimson and orange and purple. Over all, an eternal mantle of snow lay like frozen spume. Mark opened his hand and looked at the jewel he held. It was pulsing now with a fiery radiance. The great spacer was lying in the cup-shaped hollow of the immense valley, resting on the blanketing snow, just as once before, a tiny cruiser had rested crippled in the fantastic Europan night. But it was different then. Mark remembered his chilling awe at the Dantesque panorama, and his shock when Jim Brannigan had found life on Europa, the strange, exquisitely furred bipeds with slender arms and six-fingered hands. He had thought them animals then, despite the bright intelligence shining in the beryl-eyes of the creatures. But he'd learned differently in time, when Jim had crushed his skull from behind, and the Panadurs had saved him by absorbing Jim's life-energy and transferring it to him while he lay unconscious. That was the miracle, that the metabolism of the Panadurs could absorb energy from any source and transfer it at will. They were telepathic, and their leader had given him the jewel to facilitate communication if Mark ever returned. It was like the remembrance of a dream, to have the past pass in review through his mind as he methodically donned his allurium suit, and turned on the heating unit.