“Well, goodbye, son.”  He gripped the boy’s hand.  “Now get everybody out of here; don’t stop till you’re at the pass.”

“You’re not staying behind!” Varnis cried.  “Dard, you promised us!  I remember, when we were all in the ship together—­you and I and Analea and Olva and Dorita and Eldra and, oh, what was that other girl’s name, Kyna!  And we were all having such a nice time, and you were telling us how we’d all come to Tareesh, and we were having such fun talking about it....”

“That’s right, Varnis,” he agreed.  “And so I will.  I have something to do, here, but I’ll meet you on top of the mountain, after I’m through, and in the morning we’ll all go to Tareesh.”

She smiled—­the gentle, childlike smile of the harmlessly mad—­and turned away.  The son of Kalvar Dard made sure that she and all the children were on the way, and then he, too, turned and followed them, leaving Dard alone.

Alone, with a bomb and a task.  He’d borne that task for twenty years, now; in a few minutes, it would be ended, with an instant’s searing heat.  He tried not to be too glad; there were so many things he might have done, if he had tried harder.  Metals, for instance.  Somewhere there surely must be ores which they could have smelted, but he had never found them.  And he might have tried catching some of the little horses they hunted for food, to break and train to bear burdens.  And the alphabet—­why hadn’t he taught it to Bo-Bo and the daughter of Seldar Glav, and laid on them an obligation to teach the others?  And the grass-seeds they used for making flour sometimes; they should have planted fields of the better kinds, and patches of edible roots, and returned at the proper time to harvest them.  There were so many things, things that none of those young savages or their children would think of in ten thousand years....

Something was moving among the rocks, a hundred yards away.  He straightened, as much as his broken legs would permit, and watched.  Yes, there was one of them, and there was another, and another.  One rose from behind a rock and came forward at a shambling run, making bestial sounds.  Then two more lumbered into sight, and in a moment the ravine was alive with them.  They were almost upon him when Kalvar Dard pressed in the thumbpiece of the bomb; they were clutching at him when he released it.  He felt a slight jar....

* * * * *

When they reached the pass, they all stopped as the son of Kalvar Dard turned and looked back.  Dorita stood beside him, looking toward the waterfall too; she also knew what was about to happen.  The others merely gaped in blank incomprehension, or grasped their weapons, thinking that the enemy was pressing close behind and that they were making a stand here.  A few of the smaller boys and girls began picking up stones.

Then a tiny pin-point of brilliance winked, just below where the snow-fed stream vanished into the gorge.  That was all, for an instant, and then a great fire-shot cloud swirled upward, hundreds of feet into the air; there was a crash, louder than any sound any of them except Dorita and Varnis had ever heard before.