we waiting for?”
Presently the quartet was moving through the jungle of giant ferns. All about them was silence in the heavy gathering twilight. The bright sword of the Beam was fading, angling away as the opening in the crust was rotated away from the Sun.
Newton knew the direction of the Belt, that seared blackened strip in which the terrible heat of the Sun’s single shaft permitted nothing to live. He steered their course to head around the end of the Belt.
Again a beast-scream came from far away. There seemed no other sound in the fern jungle. But presently the Brain spoke softly. “We are being followed,” he said.
Curt Newton nodded. Simon’s microphonic ears, far more acute than any human auditory system, had picked up faint rustlings of movement among the ferns. Now that he was listening for it Newton could hear the stealthy padding of many naked feet, moving with infinite caution.
“I don’t understand it,” he murmured. “These Vulcanian natives were friendly before. This furtiveness —”
“Shall we stop and have it out with them?” Otho demanded.
“No, let’s go on. We have to find that citadel before dark. But keep alert — a thrown spear can be just as final as a blaster.”
“Not to me it can’t,” rumbled Grag.
“Curt didn’t mean you — he meant us humans,” gibed Otho.
“Listen, plastic-puss,” Grag began wrathfully. “I’m twice as human as you and —”
“That’s enough,” Newton rapped. “You can carry on that old argument some other time.”
They went on and the unseen escort went with them. Soon they encountered the end of the Belt.
Black calcined soil, smoking rocks, a wave of dull heat from the ground itself attested to the awful heat of the Sun whose single great ray once each day traveled across this strip of Vulcan’s interior.
They made Captain Future feel again the terrible power of the gigantic solar orb so close by that could reach in through a single loophole and wreak this flaming devastation where it touched.
They crossed the end of that blackened strip, Curt and Otho hastening over the hot rocks, Grag plodding stolidly, Simon gliding ahead.
Before them the fern jungle rose into olive-colored hills, growing dark as the dusk deepened. Almost at once Newton noticed something on the slope of the nearest hill. It was a raw lumpy scar where a landslide had recently occurred.
“Simon, look at that landslide! Notice anything?”
The Brain hovered, his lens-eyes surveying the dusky hillside. “Yes, the outline. Definitely unnatural.”
Otho and Grag were staring now, too. “I don’t see anything unnatural about it,” boomed the metal giant.
“It covers a building that stood on that hillside,” Newton informed him. “Look at the symmetry of it, even masked by soil — the central cupola, the two wings.”
Otho’s bright eyes flashed. “The citadel Carlin mentioned?”
“Perhaps. Let’s have a look.”
They moved on. In a brief time they were climbing the slope to that great lumpy scar of new soil.
Newton looked back down at the jungle. No one had followed them out of it onto the bare slope. The giant ferns stretched far away and he could catch the tawny gleam of Yellow Lake in the distant dusk.
THROUGH the twilight jungle, the Belt stretched like a stygian river of deepest black. He could see no building or ruin of any kind on his side of the ebon strip.
“This must be the citadel Carlin meant,” he said. “Apparently a landslide has covered it since he was here. We’ll have to dig a way in.”
They found flat stones in the loose soil of the slide. Using them as hand-spades Newton and the android and robot began pushing aside the ocher soil above the cupola of the buried building.
Something flashed and hissed in the dusk. Curt Newton whirled. A long quivering spear stuck in the slope some distance below them.
“I thought the Vulcanians were still with us!” Otho muttered.
Newton said quietly, “Just stand still. Let