They didn’t know that, but there was some reason to think the Sheem Spider would be no menace to them afterwards. It must have instructions not to kill in this situation — at least not to kill indiscriminately — until the Agandar had Goth safe. The instructions might hold it in check when they shot down Yango. Or they might not.

Something like a short, hard cannon-crack tore the air high above the valley, startled them both into lifting their heads. They looked at each other.

“Thunder,” the captain said quietly. “I’ve been hearing some off and on. The sound came again as he spoke, more distantly and from another angle, far off in the mountains.”

“No,” Hulik said, “it’s them. They’re looking for us.”

He glanced at her uneasily. She nodded towards the valley. “It goes with the great, deep sound we heard down there — and other things. They’ve been moving around us. Circling. They’re looking for us and they’re coming closer.”

“Who’s looking for us?” asked the captain.

“The owners of this world. We’ve disturbed them and they don’t like visitors. The things that’ve been following us are their spies. Old Horny was a spy — he flew off to tell about us. A while ago a shadow was moving along the other side of the valley. I thought they’d discovered us then but it went away again. It’s because we’re so small, I think. They don’t know what they’re looking for, and so far they haven’t been able to find us. But they’re getting close.”

Her voice was low and even, her face quite calm. “We may stop Yango here, but I don’t think we’ll be able to get away from this world again. It’s too late for that! So it doesn’t really matter so much about the Spider.” She nodded towards the captain’s right. “It’s coming now, Captain!”

He dropped his head back behind the tangle of dusty, withered stuff he’d arranged before him, watching the thickets below on the right through it. For a moment, half screened by the growth, a pale green glimmer moved among the rocks, then disappeared again. Still perhaps two hundred yards away! He glanced briefly back at Hulik. She’d flattened down, too, gun hand next to her chin, head lifted just enough to let her peer out from the left side of the ledge. Whatever fearful and fantastic thoughts she’d developed about this red-shadowed world, she evidently didn’t intend to let them interfere with concluding their business with the Agandar. If anything, her notions seemed to be steadying her as far as the Sheem Assassin was concerned — as if that were now an insignificant terror. She might, he thought uncomfortably, be not too far from a state of lunatic indifference to what happened next.

No time to worry about it now. The green glow reappeared from around an outcropping; and with a smooth shifting of great jointed legs, the Spider moved into view, Yango riding it, gripping the narrow connecting section of the segmented body between his knees. The Spider’s head swung from side to side in a steady searching motion which seemed to keep time with the flowing walk; the paired jaws opened and closed. Seen at this small distance, it was difficult to think of it as a machine and not the awesome hunting animal which had been its model. But the machine was more deadly than the animal could ever have been…

There was the faintest of rustling noises to the captain’s left. He turned his head, very cautiously because the Sheem Spider and its rider were moving across the rock shoulder directly in front of them now, saw with a start of dismay that Hulik had lifted her gun, was easing it forward through the concealing pile of litter before her, head tilted as she sighted along it. If she triggered the blaster now -

But she didn’t. Whether she decided it was too long a shot in this dim air or remembered in time that only if they failed to trap Yango and his machine on the cliff were they to try to finish off the man, the captain couldn’t guess. But the robot’s long, gliding stride carried it on beyond a dense thicket at the left of the ledge, and it and the Agandar were out of sight again. Hulik slowly drew back her gun, remained motionless, peering down.

There was silence for perhaps a minute. Not complete silence. The captain grew aware of whisperings of sound, shadow motion, stealthy stirrings, back along the stretch the Agandar had come. Yango had brought an escort up from the valley with him, as they had… Then, off on the left, some distance away, he heard the heavy singsong snarl of the Sheem Spider.

Hulik twisted her head towards him, lips silently shaping the word “Vezzarn.” He nodded. The pursuit seemed checked for the moment at the point where Vezzarn’s trail had turned away from theirs.

The snarls subsided. Silence again… and after some seconds he knew Yango was on his way back, because the minor rustlings below ended. The unseen escort was falling back as the robot approached. Perhaps another minute passed. He glanced over at Hulik, saw a new tension in her. But there was nothing visible as yet from his side of the ledge. The massively curved jut of the rock cut off part of his view.

Then, over a hundred yards down, on the sloping ground at the foot of the cliff, the Sheem Spider came partly out from under the ledge. Two of the thick, bristling legs appeared first, followed by the head and a forward section of the body. It moved with stealthy deliberation, stopped again and stood dead still, head turned up, the double jaws continuing a slow chewing motion. He could make out the line of small, bright-yellow eyes across the upper part of the big head, but there was not enough of the thing in sight to tell him whether Yango was still on its back. Hulik knew, of course. The robot must have come gliding quietly through the thickets on their left and emerged almost directly below her.

Shifting very cautiously — the thing seemed to be staring straight up at him — the captain turned his head behind his flimsy barricade, looked over at Hulik. She had her gun ready again, was sighting down along it, unmoving. The gun wasn’t aimed at the Spider; the angle wasn’t steep enough for that. So Yango -

The captain’s eyes searched the part of the thickets he could see behind the robot. Something moved slightly there, moved again, stopped. A half-crouched figure interested in keeping as much screening vegetation as it could between itself and possible observers from above. The Agandar.

The Spider still hadn’t stirred. The captain inched his gun forwards, brought it to bear on the center of the crouching man-shape. Not too good a target in that tangle, if it came to shooting! But perhaps it wouldn’t. If the robot’s sensor equipment couldn’t detect them here, if they made no incautious move, Yango still might decide they weren’t in the immediate neighborhood and remount the thing before it began its ascent along their trail…

That thought ended abruptly.

The robot reared, front sets of legs spread, swung in towards the cliff face and, with that, passed again beyond the captain’s limited range of vision. He didn’t see the clawed leg tips reach up, test the rough rock for holds and settle in; but he could hear them. Then there were momentary glimpses of the thing’s shaggy back, as it drew itself off the ground and came clambering up towards the ledge.

Heart thudding, he took up the slack on the trigger, held the gun pointed as steadily as he could at Yango’s half hidden shape. When he heard Hulik’s blaster, he’d fire, too, at once. But otherwise wait — a few seconds longer; wait, in fact, as long as he possibly could! For Yango might move, present a better target, or he might discover some reason to check the robot’s ascent before it reached the ledge. If they fired now and missed -

Sudden rattle and thud of dislodged rock below! The section of the robot’s back he could see at the moment jerked sharply. The thing had lost a hold, evidently found another at once for it was steady again — and startlingly close! Already it seemed to have covered more than half the distance to the ledge.