The pony stood huge and chunky beside her, its forefeet on the edge of the hollow, staring down. Muddy water trickled from its knobby flanks. It had brought the warm mud-smells of a summer pond back with it to hang in a cloud about them.
There was vague, dark, continuous motion at the bottom of the hollow. A barely noticeable stirring in the single big pool of darkness that filled it.
“If I were alone,” the pony said, “I’d get out of here! I know when I ought to be scared. But you’ve taken psychological control of my reactions, haven’t you?”
“Yes,” said Grandma. “It’ll be easier for me, though, if you help along as much as you can. There’s really no danger until their transmitter has come through.”
“Unless,” said the pony, “they’ve worked out some brand-new tricks in the past few hundred years.”
“There’s that,” Grandma admitted. “But they’ve never tried changing their tricks on us yet. If it were us doing the attacking, we’d vary our methods each time, as much as we could. But the Halpa don’t seem to think just like we do about anything. They wouldn’t still be so careful if they didn’t realize they were very vulnerable at this point.”
“I hope they’re right about that!” the pony said briefly.
Its head moved then, following the motion of something that sailed flutteringly out of the depths of the hollow, circled along its far rim, and descended again. The inhabitants of Treebel had a much deeper range of dark-vision than Grandma Wannattel, but she was also aware of that shape.
“They’re not much to look at,” the pony remarked. “Like a big, dark rag of leather, mostly.”
“Their physical structure is believed to be quite simple,” Grandma agreed slowly. The pony was tensing up again, and it was best to go on talking to it, about almost anything at all. That always helped, even though the pony knew her much too well by now to be really fooled by such tricks.
“Many very efficient life-forms aren’t physically complicated, you know,” she went on, letting the sound of her voice ripple steadily into its mind. “Parasitical types, particularly. It’s pretty certain, too, that the Halpa have the hive-mind class of intelligence, so what goes for the nerve-systems of most of the ones they send through to us might be nothing much more than secondary reflex-transmitters. . . .”
Grimp stirred in his sleep at that point and grumbled. Grandma looked down at him. “You’re sound asleep!” she told him severely, and he was again.
“You’ve got plans for that boy, haven’t you?” the pony said, without shifting its gaze from the hollow.
“I’ve had my eye on him,” Grandma admitted, “and I’ve already recommended him to Headquarters for observation. But I’m not going to make up my mind about Grimp till next summer, when we’ve had more time to study him. Meanwhile, we’ll see what he picks up naturally from the lortel in the way of telepathic communication and sensory extensions. I think Grimp’s the kind we can use.”
“He’s all right,” the pony agreed absently. “A bit murderous, though, like most of you . . .”
“He’ll grow out of it!” Grandma said, a little annoyedly, for the subject of human aggressiveness was one she and the pony argued about frequently. “You can’t hurry developments like that along too much. All of Noorhut should grow out of that stage, as a people, in another few hundred years. They’re about at the turning-point right now—”
Their heads came up together, then, as something very much like a big, dark rag of leather came fluttering up from the hollow and hung in the dark air above them. The representatives of the opposing powers that were meeting on Noorhut that night took quiet stock of one another for a moment.
The Halpa was about six feet long and two wide, and considerably less than an inch thick. It held its position in the air with a steady, rippling motion, like a bat the size of a man. Then, suddenly, it extended itself with a snap, growing taut as a curved sail.
The pony snorted involuntarily. The apparently featureless shape in the air turned towards it and drifted a few inches closer. When nothing more happened, it turned again and fluttered quietly back down into the hollow.
“Could it tell I was scared?” the pony asked uneasily.
“You reacted just right,” Grandma said soothingly. “Startled suspicion at first, and then just curiosity, and then another start when it made that jump. It’s about what they’d expect from creatures that would be hanging around the hollow now. We’re like cows to them. They can’t tell what things are by their looks, like we do—”
But her tone was thoughtful, and she was more shaken than she would have cared to let the pony notice. There had been something indescribably menacing and self-assured in the Halpa’s gesture. Almost certainly, it had only been trying to draw a reaction of hostile intelligence from them, probing, perhaps, for the presence of weapons that might be dangerous to its kind.
But there was a chance—a tiny but appalling chance—that the things had developed some drastically new form of attack since their last breakthrough, and that they already were in control of the situation . . .
In which case, neither Grimp nor anyone else on Noorhut would be doing any more growing-up after tomorrow.
Each of the eleven hundred and seventeen planets that had been lost to the Halpa so far still traced a fiery, forbidding orbit through space—torn back from the invaders only at the cost of depriving it, by humanity’s own weapons, of the conditions any known form of life could tolerate.
The possibility that this might also be Noorhut’s future had loomed as an ugly enormity before her for the past four years. But of the nearly half a hundred worlds which the Halpa were found to be investigating through their detector-globes as possible invasion points for this period, Noorhut finally had been selected by Headquarters as the one where local conditions were most suited to meet them successfully. And that meant in a manner which must include the destruction of their only real invasion weapon, the fabulous and mysterious Halpa transmitter. Capable as they undoubtedly were, they had shown in the past that they were able or willing to employ only one of those instruments for each period of attack. Destroying the transmitter meant therefore that humanity would gain a few more centuries to figure out a way to get back at the Halpa before a new attempt was made.
So on all planets but Noorhut the detector-globes had been encouraged carefully to send back reports of a dangerously alert and well-armed population. On Noorhut, however, they had been soothed along . . . and just as her home-planet had been chosen as the most favorable point of encounter, so was Erisa Wannattel herself selected as the agent most suited to represent humanity’s forces under the conditions that existed there.
Grandma sighed gently and reminded herself again that Headquarters was as unlikely to miscalculate the overall probability of success as it was to select the wrong person to achieve it. There was only the tiniest, the most theoretical, of chances that something might go wrong and that she would end her long career with the blundering murder of her own homeworld.
But there was that chance.
* * *
“There seem to be more down there every minute!” the pony was saying.
Grandma drew a deep breath.
“Must be several thousand by now,” she acknowledged. “It’s getting near breakthrough time, all right, but those are only the advance forces.” She added, “Do you notice anything like a glow of light down there, towards the center?”
The pony stared a moment. “Yes,” it said. “But I would have thought that was way under the red for you. Can you see it?”
“No,” said Grandma. “I get a kind of a feeling, like heat. That’s the transmitter beginning to come through. I think we’ve got them!”
The pony shifted its bulk slowly from side to side.
“Yes,” it said resignedly, “or they’ve got us.”
“Don’t think about that,” Grandma ordered sharply and clamped one more mental lock shut on the foggy, dark terrors that were curling and writhing under her conscious thoughts, threatening to emerge at the last moment and paralyze her actions.
She had opened her black bag and was unhurriedly fitting together something composed of a few pieces of wood and wire, and a rather heavy, stiff spring . . .
“Just be ready,” she added.
“I’ve been ready for an hour,” said the pony, shuffling its feet unhappily.
They did no more talking after that. All the valley had become quiet about them. But slowly the hollow below was filling up with a black, stirring, slithering tide. Bits of it fluttered up now and then like strips of black smoke, hovered a few yards above the mass, and settled again.