If the miniscule amount of animal husbandry on Mars used up the atmosphere too rapidly, the entire Earth settlement project, which already numbered almost a million human beings, would be imperilled. You couldn’t feed a million men and women on what could be brought from the home planet in space cargo vessels. But how could you get rain when there was no moisture in the atmosphere, almost no atmosphere to moisten? It was, Lynne decided, the most frighteningly disheartening of vicious cycles. The ship came out of the atmospheric dead spot and the fear and confusion of Nampura Depot encroached alarmingly on Lynne’s thoughts again. So difficult was it to follow the babel of minds that she gave up and waited impatiently while the transport described its slow downward parabola to come to rest, in the violet dusk, on the flare-lit airfield of the Depot. She thanked the captain for his courtesy and hopped a supply truck to the Depot proper. As the newest of official structures built by Earthmen on Mars, the Depot represented the most advanced attempts to develop an architectural blend between terrestrial utilitarianism and the eclectic delicacy of ancient Martian building wizardry. In daylight, it looked to Lynne like a Quonset hut with flying buttresses. She was grateful for the darkness, as the supply truck rolled up to its service gate. Tony Willis, the non-telepathic, stout, bespectacled communications wizard who served as Depot Seneschal, greeted Lynne with a hug and a “_Crehut_, I’m glad you’re here, angel. Something pretty ugly has happened. Where’s Rolf?” “Something happened to him, too--he got drunk at the weddings,” said Lynne, stepping out of her coverall. “But I’d like to know just how serious the situation here is, Tony. I got some pretty mixed-up flashes on the transport. Am I right in believing that poor Juan is dead--and Rana still unconscious.” “Total blackout,” said Willis grimly, escorting her to the cubicle that served as his office, a windowless, brightly-lighted room decorated with the wiry, brown-skinned maidens that passed as pinup girls on Mars. Seated behind a desk across from her, he said, “You know I’m a mess on this TP stuff. But Juan and Rana were on to something. They’ve been thick as the proverbial thieves, waiting for you and Rolf to get away so they could do some experimenting on their own. Then, about an hour ago--” He looked at her, and his lips tightened--“Juan was flattened as if a ’dozer had passed over him and Rana was blasted against the wall of the Rec Room and hasn’t come out of it since.” “An explosion?” Lynne asked swiftly, anxiously. Tony Willis shook his sandy head. “Not the way you think,” he told her. “Oh, there was an explosion, all right. It blew the Rec Room all to hell and gone. _But it had no mechanical origin!_”