As one of the Guardian ships protecting Earth, the crew had a problem to solve. Just how do you protect a race from an enemy who can take over a man’s mind without seeming effort or warning?

“That hand didn’t move, did it?” Edwardson asked, standing at the port, looking at the stars.

“No,” Morse said. He had been staring fixedly at the Attison Detector for over an hour. Now he blinked three times rapidly, and looked again. “Not a millimeter.”

“I don’t think it moved either,” Cassel added, from behind the gunfire panel. And that was that. The slender black hand of the indicator rested unwaveringly on zero. The ship’s guns were ready, their black mouths open to the stars. A steady hum filled the room. It came from the Attison Detector, and the sound was reassuring. It reinforced the fact that the Detector was attached to all the other Detectors, forming a gigantic network around Earth.

“Why in hell don’t they come?” Edwardson asked, still looking at the stars. “Why don’t they hit?”

“Aah, shut up,” Morse said. He had a tired, glum look. High on his right temple was an old radiation burn, a sunburst of pink scar tissue. From a distance it looked like a decoration.

“I just wish they’d come,” Edwardson said. He returned from the port to his chair, bending to clear the low metal ceiling. “Don’t you wish they’d come?” Edwardson had the narrow, timid face of a mouse; but a highly intelligent mouse. One that cats did well to avoid.

“Don’t you?” he repeated.

The other men didn’t answer. They had settled back to their dreams, staring hypnotically at the Detector face.

“They’ve had enough time,” Edwardson said, half to himself.

Cassel yawned and licked his lips. “Anyone want to play some gin?” he asked, stroking his beard. The beard was a memento of his undergraduate days. Cassel maintained he could store almost fifteen minutes worth of oxygen in its follicles. He had never stepped into space unhelmeted to prove it.

Morse looked away, and Edwardson automatically watched the indicator. This routine had been drilled into them, branded into their subconscious. They would as soon have cut their throats as leave the indicator unguarded.

“Do you think they’ll come soon?” Edwardson asked, his brown rodent’s eyes on the indicator. The men didn’t answer him. After two months together in space their conversational powers were exhausted. They weren’t interested in Cassel’s undergraduate days, or in Morse’s conquests.

They were bored to death even with their own thoughts and dreams, bored with the attack they expected momentarily.

“Just one thing I’d like to know,” Edwardson said, slipping with ease into an old conversational gambit. “How far can they do it?”

They had talked for weeks about the enemy’s telepathic range, but they always returned to it.

As professional soldiers, they couldn’t help but speculate on the enemy and his weapons. It was their shop talk.

“Well,” Morse said wearily, “Our Detector network covers the system out beyond Mars’ orbit.”

“Where we sit,” Cassel said, watching the indicators now that the others were talking.

“They might not even know we have a detection unit working,” Morse said, as he had said a thousand times.

“Oh, stop,” Edwardson said, his thin face twisted in scorn. “They’re telepathic. They must have read every bit of stuff in Everset’s mind.”

“Everset didn’t know we had a detection unit,” Morse said, his eyes returning to the dial. “He was captured before we had it.”

“Look,” Edwardson said, “They ask him, ’Boy, what would you do if you knew a telepathic race was coming to take over Earth? How would you guard the planet?’”

“Idle speculation,” Cassel said. “Maybe Everset didn’t think of this.”

“He thinks like a man, doesn’t he? Everyone agreed on this defense. Everset would, too.”

“Syllogistic,” Cassel murmured. “Very shaky.”

“I sure wish he hadn’t been captured,” Edwardson said.

“It could have been worse,” Morse put in, his face sadder than ever. “What if they’d captured both of them?”

“I wish they’d come,” Edwardson said.

Richard Everset and C. R. Jones had gone on the first interstellar flight. They had found an inhabited planet in the region of Vega. The rest was standard procedure.

A flip of the coin had decided it. Everset went down in the scouter, maintaining radio contact with Jones, in the ship.

The recording of that contact was preserved for all Earth to hear.

“Just met the natives,” Everset said. “Funny-looking bunch. Give you the physical description later.”

“Are they trying to talk to you?” Jones asked, guiding the ship in a slow spiral over the planet.

“No. Hold it. Well I’m damned! They’re telepathic! How do you like that?”

“Great,” Jones said. “Go on.”

“Hold it. Say, Jonesy, I don’t know as I like these boys. They haven’t got nice minds. Brother!”

“What is it?” Jones asked, lifting the ship a little higher.

“Minds! These bastards are power-crazy. Seems they’ve hit all the systems around here, looking for someone to ”

“Yeh?”

“I’ve got that a bit wrong,” Everset said pleasantly. “They are not so bad.”

Jones had a quick mind, a suspicious nature and good reflexes. He set the accelerator for all the G’s he could take, lay down on the floor and said, “Tell me more.”

“Come on down,” Everset said, in violation of every law of spaceflight. “These guys are all right. As a matter of fact, they’re the most marvelous ”

That was where the recording ended, because Jones was pinned to the floor by twenty G’s acceleration as he boosted the ship to the level needed for the C-jump.

He broke three ribs getting home, but he got there.

A telepathic species was on the march. What was Earth going to do about it?

A lot of speculation necessarily clothed the bare bones of Jones’ information. Evidently the species could take over a mind with ease. With Everset, it seemed that they had insinuated their thoughts into his, delicately altering his previous convictions. They had possessed him with remarkable ease.

How about Jones? Why hadn’t they taken him? Was distance a factor? Or hadn’t they been prepared for the suddenness of his departure?

One thing was certain. Everything Everset knew, the enemy knew. That meant they knew where Earth was, and how defenseless the planet was to their form of attack.

It could be expected that they were on their way.

Something was needed to nullify their tremendous advantage. But what sort of something? What armor is there against thought? How do you dodge a wavelength?

Pouch-eyed scientists gravely consulted their periodic tables.

And how do you know when a man has been possessed? Although the enemy was clumsy with Everset, would they continue to be clumsy? Wouldn’t they learn?

Psychologists tore their hair and bewailed the absence of an absolute scale for humanity.

Of course, something had to be done at once. The answer, from a technological planet, was a technological one. Build a space fleet and equip it with some sort of a detection-fire network.

This was done in record time. The Attison Detector was developed, a cross between radar and the electroencephalograph. Any alteration from the typical human brain wave pattern of the occupants of a Detector-equipped ship would boost the indicator around the dial. Even a bad dream or a case of indigestion would jar it.

It seemed probable that any attempt to take over a human mind would disturb something. There had to be a point of interaction, somewhere.

That was what the Attison Detector was supposed to detect. Maybe it would.

The spaceships, three men to a ship, dotted space between Earth and Mars, forming a gigantic sphere with Earth in the center.

Tens of thousands of men crouched behind gunfire panels, watching the dials on the Attison Detector.

The unmoving dials.

“Do you think I could fire a couple of bursts?” Edwardson asked, his fingers on the gunfire button. “Just to limber the guns?”

“Those guns don’t need limbering,” Cassel said, stroking his beard. “Besides, you’d throw the whole fleet into a panic.”

“Cassel,” Morse said, very quietly. “Get your hand off your beard.”

“Why should I?” Cassel asked.

“Because,” Morse answered, almost in a whisper, “I am about to ram it right down your fat throat.”

Cassel grinned and tightened his fists. “Pleasure,” he said. “I’m tired of looking at that scar of yours.” He stood up.

“Cut it,” Edwardson said wearily. “Watch the birdie.”

“No reason to, really,” Morse said, leaning back. “There’s an alarm bell attached.” But he looked at the dial.

“What if the bell doesn’t work?” Edwardson asked. “What if the dial is jammed? How would you like something cold slithering into your mind?”

“The dial’ll work,” Cassel said. His eyes shifted from Edwardson’s face to the motionless indicator.

“I think I’ll sack in,” Edwardson said.

“Stick around,” Cassel said. “Play you some gin.”

“All right.” Edwardson found and shuffled the greasy cards, while Morse took a turn glaring at the dial.

“I sure wish they’d come,” he said.

“Cut,” Edwardson said, handing the pack to Cassel.

“I wonder what our friends look like,” Morse said, watching the dial.

“Probably remarkably like us,” Edwardson said, dealing the cards. Cassel picked them up one by one, slowly, as if he hoped something interesting would be under them.

“They should have given us another man,” Cassel said. “We could play bridge.”

“I don’t play bridge,” Edwardson said.

“You could learn.”

“Why didn’t we send a task force?” Morse asked. “Why didn’t we bomb their planet?”

“Don’t be dumb,” Edwardson said. “We’d lose any ship we sent. Probably get them back at us, possessed and firing.”

“Knock with nine,” Cassel said.

“I don’t give a good damn if you knock with a thousand,” Edwardson said gaily. “How much do I owe you now?”

“Three million five hundred and eight thousand and ten. Dollars.”

“I sure wish they’d come,” Morse said.

“Want me to write a check?”

“Take your time. Take until next week.”

“Someone should reason with the bastards,” Morse said, looking out the port. Cassel immediately looked at the dial.

“I just thought of something,” Edwardson said.

“Yeh?”

“I bet it feels horrible to have your mind grabbed,” Edwardson said. “I bet it’s awful.”

“You’ll know when it happens,” Cassel said.

“Did Everset?”

“Probably. He just couldn’t do anything about it.”

“My mind feels fine,” Cassel said. “But the first one of you guys starts acting queer watch out.”

They all laughed.

“Well,” Edwardson said, “I’d sure like a chance to reason with them. This is stupid.”

“Why not?” Cassel asked.

“You mean go out and meet them?”

“Sure,” Cassel said. “We’re doing no good sitting here.”

“I should think we could do something,” Edwardson said slowly. “After all, they’re not invincible. They’re reasoning beings.”

Morse punched a course on the ship’s tape, then looked up.

“You think we should contact the command? Tell them what we’re doing?”

“No!” Cassel said, and Edwardson nodded in agreement. “Red tape. We’ll just go out and see what we can do. If they won’t talk, we’ll blast ’em out of space.”

“Look!”

Out of the port they could see the red flare of a reaction engine; the next ship in their sector, speeding forward.

“They must have got the same idea,” Edwardson said.

“Let’s get there first,” Cassel said. Morse shoved the accelerator in and they were thrown back in their seats.

“That dial hasn’t moved yet, has it?” Edwardson asked, over the clamor of the Detector alarm bell.

“Not a move out of it,” Cassel said, looking at the dial with its indicator slammed all the way over to the highest notch.