The Oan saw him coming and straightened, allowing the girl to fall. He set his twisted legs and bared his fangs. The fur on his back stood out straight as he prepared to meet the young Martian's attack.

Ro struck his foe head on. They went down in a frenzied bundle of fury. The rat man's tail lashed out to twist around Ro's neck. With frantic strength, Ro tore it away before it could tighten.

Ignoring the Oan's slashing teeth, the young Martian pounded heavy fists into his soft stomach. Suddenly shifting his attack, Ro wrapped his legs around the rat man's waist. His hands caught a furry throat and tightened.

Over and over they rolled. The Oan clawed urgently at the Martian's choking fingers. His chest made strange noises as it pleaded for the air that would give it life. But Ro's hands were bands of steel, tightening, ever tightening their deadly grip.

Then, as suddenly as it had started, it was over. The rat man quivered and lay still.

Ro dismounted the limp body. His face wore a wildly triumphant expression. It changed as he remembered the girl. He ran to her side.

Na was just opening her eyes. She stared around her fearfully, then smiled as she recognized Ro. The young Martian breathed a sigh of relief.

Na turned her head and saw the body of the rat man. She shuddered.

"I was coming down the side of the mountain," she said. "I saw him standing at the foot. The shadows were deceiving. I thought it was you. It wasn't until too late that I discovered my mistake."

Ro gathered the girl in his arms. He spoke softly to her to help her forget.

When she had recovered from her shock, the small group traveled on. Ro led them about a mile further along the base of the cliff, then up, to a cleverly concealed cave.

"We will stay here," he told the others, "until we are ready to attack the Oan."

"But there are only six of us," one of the white men protested. "There are hundreds of the beasts. We wouldn't have a chance."

Ro smiled.

"We will speak of that when it is dawn again," he said with his thoughts. "Now we must rest."

He sat in a corner of the cave and leaned back against the wall. His eyes were half shut and he pretended to doze. Actually he was studying the white ones.

The man with the silver hair seemed very old and weak, but very wise. The other men had hair as black as any Martian's, but their skin was pure white. They were handsome, Ro thought, in a barbaric sort of way. One was lean and determined, the other, equally determined, but stouter and less impressive. Ro then centered his attention on the girl. Her golden hair gleamed proudly, even in the dusk. She was very beautiful, almost as lovely as Na.

"Tell me," he asked suddenly, "where is this strange place you come from? And how is it that you can speak and cause others to speak with their minds?"

It was the old man who answered.

"We come from a place called Earth, many millions of miles away through space. My daughter, Charlotte, my two assistants, Carlson—" the lean man nodded—"Grimm—" the stouter man acknowledged the introduction—"and myself are an expedition. We came here to Mars to study."

Ro introduced himself and Na.

"What manner of a place is this Earth?" he asked, after the formalities.

"Our part of Earth, America, is a great country. Our cities are built of steel and stone, and we travel about in space boats. Now tell me, what is it like here on Mars? Surely the whole planet isn't wilderness. What year is it?"

"You have seen what it is like here," Ro answered. "As for 'year,' I don't understand."

"A year is a measure of time," the old man explained. "When we left Earth it was the year twenty-two hundred."

"We have nothing like that here," said Ro, still puzzled. "But tell me, about this speaking with the mind. Perhaps I shall understand that."

"It's simple telepathy. We have mastered the science on Earth. It takes study from childhood, but once you have mastered the art, it is quite simple to transmit or receive thoughts from anyone. A mere matter of concentration. We—who speak different tongues—understand each other because of action we have in mind as we speak. We want the other to walk, we think of the other walking. A picture is transmitted and understood. It is a message in a Universal language."

Ro sighed.

"I am afraid we are very backward here on Mars," he said wearily. "I would like to learn more, but we must sleep now. Tomorrow will be a very busy day."

Ro slipped his arm about Na's shoulder and drew her closer. With their heads together they slept.

Ro awakened with the dawn. He was startled to find that Na had left his side. He rose quickly and strode to the mouth of the cave.

Na met him at the entrance. She was returning from a clump of trees a short distance away. Her arms were loaded with Manno, the fruit of Mars, and clusters of wild berries and grapes.

"You see," she said, "I will make you a good mate. Our table will be well provided for."

"You will make no mate at all," Ro said sternly, "and there will be no table if you wander off. Your next meeting with the Oan may not be so fortunate."

He glared at her for a moment, then smiled and helped her with her burden.

The others in the cave awakened. Ro noticed that Charlotte had slept beside Carlson, but moved away shyly now that it was daylight. He noticed, too, that Grimm was seeing the same thing and seemed annoyed.

Ro smiled. These young white men were no different than Martians where a girl was concerned.

When they had finished breakfast, they sat around the floor of the cave and spoke.

It was Carlson who asked, "How do you expect the six of us to attack the rat men?"

"The Oan are cowards," Ro answered. "They are brave only because they have your weapons. But now that you are free, you can make more of these sticks that shoot fire."

Grimm laughed.

"It takes intricate machinery to construct a ray gun," he said. "Here in this wilderness we have sticks and stones to work with."

Ro sprang to his feet to tower above the man. His handsome face was twisted in anger.

"You're lying," he shouted aloud, forgetting that the white man couldn't understand his words. "You're lying because you are afraid. You refuse to help me avenge my people because you are more of a coward than the Oan."

Grimm climbed to his feet and backed away. Ro advanced on him, his fists clenched.

The old man also rose. He placed a restraining hand on Ro's arm.

"He's lying," said Ro with his thoughts.

"Tell him I'm speaking the truth, professor," said Grimm aloud.

The professor repeated Grimm's words with his thoughts. "It would be impossible to make new guns here," he said. "But there is another way. I have thought about it all night."

Ro turned quickly.

"What is it?" he demanded.

"The space sphere. There are weapons on our ship that are greater than ray guns. With those we could defeat the rat men." The professor shrugged, turned away. "But how could we get into the ship? It is too well guarded."

Ro fell silent. He walked to the mouth of the cave and stared out. When he turned back to the others, his attention was centered on Na.

"Perhaps the attraction you seem to hold for the Oan can be put to good use," he said aloud. "The sphere is a distance away from the Oan camp. All of the rat men cannot be guarding it. Perhaps, by revealing yourself, you can lure the guards away from their post."

He repeated his plan to the others.

"But they'll kill her," gasped Charlotte.

"She will be a woman alone," said Ro. "The Oan prefer to capture women when they can."

"Then she'll be captured," the professor said. "It's much too risky."

Ro laughed.

"Do you think I will let her go alone? I will be close by. Na can lead the rat men through a narrow part of the valley. I will be above on the cliffs, waiting to pelt them with stones. Carlson or Grimm can be with me to roll an avalanche of rocks on their heads.

"In the meantime, you can take over the unguarded sphere. The rest will be easy."

The professor smacked his fist into his palm.

"It might work at that. Grimm can go with you. Carlson and Charlotte will go with me."

"Why me?" Grimm demanded. "Why not Carlson? Or are you saving him for your daughter?"

Carlson grabbed Grimm by the shoulder and spun him around. He drove a hard fist into the stout man's face.

Grimm stumbled backward. He fell at the cave's entrance. His hand, sprawled behind him to stop his fall, closed over a rock. He flung it at Carlson from a sitting position. It caught Carlson in the shoulder.

Gritting his teeth, Carlson charged at Grimm. But Ro moved more swiftly. He caught the white man and forced him back.

"This is no time for fighting," he said. "When the Oan are defeated you can kill each other. But not until then."

Grimm brushed himself off as he got to his feet

"Okay," he sneered. "I'll go with the red man. But when we meet again, it will be a different story."

Carlson turned to Ro.

"I'll go with you," he said. "Grimm can go with Charlotte and the professor."

When they had detailed their plan, the party left the cave. Ro led them into the thickest part of the forest and toward the Oan camp.

They moved swiftly. Before long they were at the narrow entrance to the valley. It was about a hundred yards long and twenty feet wide. The walls of the cliff rose almost straight up on both sides.

"We leave you here," said Ro to the professor. "Na will lead you to the sphere. She will remain hidden until you have circled away from her. Then she will reveal herself."

Ro looked at Na for a long moment before they parted. He grew very proud of what he saw. There was no fear in her eyes. Her small chin was firm.

He turned to Carlson. The young Earthman was looking at Charlotte in much the same way.

"Come on," Ro said. "If we spend the rest of the morning here, the Oan will try some strategy of their own."

Carlson seemed to come out of a trance. He swung around to trail Ro up the sloping part of the mountain. They climbed in silence.

Once Ro stopped to look down into the valley. But Na and the others were gone. He felt a pang of regret as he turned to move upward.

When they had reached the top, he and Carlson set to work piling rocks and boulders at the edge of the cliff. They chose the point directly over the narrowest part of the valley. If all went well, the Oan would be trapped. They would die under a hailstorm of rock.

"You would have liked a more tender goodbye with Charlotte," Ro said to Carlson as they worked. "Was it fear of Grimm that prevented it?"

Carlson straightened. He weighed Ro's words before answering. Finally he said, "I didn't want to make trouble. It was a bad time, and senseless, besides. Charlotte and I are planning to be married when we return to America. It's not as though Grimm was still in the running. I'm sure he'll see reason when we tell him. It's foolish to be enemies."

"Why don't you take her for your wife here on Mars? That would end the trouble completely."

Carlson seemed surprised.

"It wouldn't be legal. Who would perform the ceremony?"

Ro seemed puzzled, then he laughed.

"Last night I thought that we on Mars are backward. Now I'm not so sure. When we find our mates here, we take her. There is no one to speak of 'legal' or 'ceremony.' After all, it's a personal matter. Who can tell us whether it is 'legal' or not? What better ceremony than a kiss and a promise?" He bent back to his work chuckling.

"I could argue the point," Carlson laughed. "I could tell you about a place called Hollywood. Marriage and divorce is bad enough there. Under your system, it would really be a mess. But I won't say anything. Here on Mars your kiss and a promise is probably as binding as any ceremony."

Ro didn't speak. He didn't concentrate and transmit his thoughts, but kept them to himself. The pictures he'd received from Carlson were confusing. The business at hand was more grim and important than untangling the puzzle.

They finished their work and seated themselves close to the edge of the cliff. Carlson was impatient. The inactivity rasped on his nerves. Ro stared anxiously at the spot where Na would make her appearance. The waiting was hard for him, too. Pictures of the girl stumbling and being caught in her chase with the rat men flashed through his mind. He flinched at what would happen then. It would cost, not only his own life, but the lives of those who had gone to the sphere.

Suddenly his fears were wiped away. Na appeared at the point he watched. She burst from the woods, running swiftly. A few seconds later, five rat men came into sight. One of them carried a ray gun.

The running figures looked tiny from the height of the cliff. They would make very poor targets. But a glance at the narrow point below reassured Ro. Even if the stones went wild, they would still land in that small area. There was no chance of their missing.

Na had entered the narrow strip. She seemed to be tiring. The rat men gained. Ro bit his lower lip and clutched the stones in his hands more tightly. Carlson crouched behind the larger rocks and boulders, ready to roll them over the ledge.

The rat men entered the pass.

Na had already passed below and was almost to the end, when she stumbled. Her head struck the hard ground as she pitched forward and she lay still.

Ro's heart leaped in his breast.

"Now!" he shouted, and let fly with one of his stones.

The missile left his hand with terrific speed. All the frantic strength in his arm was behind it. It flew straight to its mark. The Oan carrying the ray gun dropped like a log.

Carlson shoved the heaviest boulders off the ledge. He worked furiously, moving from one to the next. They fell like a thunderclap on the rat men below.

But Ro had given the signal too late. Three of the Oan were crushed under the barrage. But one moved too swiftly. He passed under the falling stones unharmed and raced toward the fallen Na.

Ro drew back his arm. His pounding heart made it difficult to aim. The stone left his hand in a powerful sweep, but went wild.

The rat man was less than thirty feet from Na. When he reached her it would be too late.

Ro snatched up another stone. He forced himself to be calm as he took deliberate aim. He made the throw smoothly.

The stone sped from his hand. It streaked down on the racing Oan and found its mark in the small of his back. The rat man threw up his arms and collapsed a few feet from his goal.

Carlson pounded Ro's back jubilantly. The young Martian smiled at the Earthman's enthusiasm. Then, quieting the elation he felt, he grew serious.

"Perhaps our friends have not fared so well," he said with his thoughts. "If we find that they have succeeded, we will have real cause to celebrate."

Carlson sobered.

"If only they have succeeded," he said aloud. "If Charlotte—"

Ro couldn't understand the words, but Carlson's feelings were clear. He could understand that the Earthman would be anxious about Charlotte.

He placed his hand on Carlson's shoulder in a comradely gesture.

"I have a feeling that all is well," he said, wondering how true his thought would prove.

The two men left the ledge and retraced their steps back to the valley. When they reached the foot of the cliff, Na was standing there waiting for them. Ro took her in his arms.

"My stumbling princess," he sighed. "I don't know how you would exist without me."

"I would fare very well," she answered, feigning haughtiness. "I only get myself in trouble to let you enjoy being a hero."

A thought transmitted by Carlson interrupted their talk.

"We must hurry. They may need us." He had retrieved the ray gun the rat man had carried and was fingering the trigger impatiently. "They have only two of these now," he said, "but they will do plenty of damage."

They set off in the direction of the sphere. Ro carried a stone in either hand, ready for instant use.

Carlson urged them constantly to hurry. But Ro needed no urging. He led them at a fast pace through the forest. In a short while they could see the gleaming sides of the sphere.

Ro signaled a halt. He moved on alone, cautiously. His eyes strained ahead for a sign of the enemy, but all was still. Even at the edge of the clearing, he met silence.

Then the door to the sphere swung wide. Grimm stepped out, smiling widely. He waved a greeting.

Ro called to Na and Carlson and stepped into the clearing.

Grimm advanced a few steps, still smiling. Then his expression changed to one of fearful surprise. His eyes were fixed on a spot to Ro's right.

Ro followed his glance. He saw three rat men standing some thirty feet away.

They were half hidden by foliage, but Ro could see that one carried a ray gun. He was sighting along the barrel, aiming at Grimm.

Ro drew back the stone in his hand. He knew in that instant, his throw would be too late.

Grimm threw up his arms instinctively to ward off the burning death he expected.

But the rat man never fired. A lance of flame seared past Ro from behind him. The rat man holding the gun screamed in pain as the charge burned into his chest. He fell forward.

Ro released the rock in his hand, but it went wild. The remaining rat men fled.

Ro turned to find Carlson holding a smoking gun.

"Lucky I happened to pick this up back there," the Earthman said.

"Very lucky," said Ro. "For Grimm's sake."

"Into the sphere," Grimm called. "Those other two will be bringing the whole tribe back."

Carlson retrieved the dead rat man's ray gun. Ro ushered Na across the clearing to the door of the sphere. Na hesitated a bit, then entered reluctantly. Ro followed, then Grimm and finally Carlson.

"I guess I owe my life to you," Grimm said, as Carlson closed the door. "And I owe you an apology for the way I acted this morning. I didn't understand how it was between you and Charlotte. She explained. It was quite a shock, but I guess I'll live. Apology accepted?"

He extended his hand.

Carlson took it sheepishly.

"Tell me," Ro interrupted, "did you meet any rat men when you took the sphere?"

Grimm shook his head.

"Those three just now are the first we've seen since we left you. When we got here the place was deserted. We—"

A cry from another section of the sphere made them turn. It was the professor's voice.

"Here they come," he shouted. "Hundreds of them."

Carlson and Grimm dashed through a doorway in the direction of the cry. Ro followed, entering a spacious room. He was taken back by the intricate machinery he saw. There were countless numbers of dials and levers, gauges and indicators.

Carlson and Grimm took their places at tiny portholes. Ro found an unoccupied post and peered out. He saw a mass of grey bodies charging toward the sphere. There were more rat men than he'd ever seen at one time before. They seemed to be climbing over one another as they raced from the forest.

A sudden whirring of machinery within the sphere caused Ro to turn from the porthole. The three Earthmen were working levers and twisting dials frantically. Additional portholes appeared in the sides of the sphere. Long tubes rose on folding legs from the floor and slid through the openings.

"Take aim," the professor shouted in a commanding voice.

The whirring within the sphere grew louder. The floor seemed to quiver underfoot as giant motors generated energy.

"Fire!"

The entire sphere shuddered. Earthquaking explosions sounded outside as charges of force left the tubes to expel their power on the grey mass in the clearing.

Charge after charge was poured into the attacking rat men.

Ro leaped back to the porthole. He saw giant craters opening in the ground. Hoarse screams of pain and terror reached his ears. Scores of Oan were literally torn apart. Others disappeared completely. Those of the attackers who lived retreated in disorder. Ro noticed that one of the retreating Oan carried a ray gun.

"Cease fire," shouted the professor.

Carlson and Grimm turned from their guns laughing.

"They won't be back," chuckled Grimm. "They'll keep running for a week."

Ro moved silently to the post Carlson had occupied. He picked up the ray gun the Earthman had laid aside.

"What do you want with that?" asked the professor. "The battle is over. There won't be any use for ray guns now. We've beaten them."

"How does it work?" Ro asked grimly. His face was hard with determination.

The professor was puzzled, but explained the workings of the gun. He finished his explanation with, "But why?"

Ro walked to the door.

"The Oan still have a gun," he said. "When you are gone, they will return to use it on my people. That must not happen."

He said no more, but left the room. Na and the others heard the door of the sphere open and slam shut.

Carlson was the first to recover his wits.

"Come on," he said. "He may need help."

The three Earthmen armed themselves and left the ship. They saw Ro disappear into the wood and took after him.

Ro moved swiftly and silently. He slipped through the underbrush like an elusive phantom.

Some distance from the sphere he saw a grey shadow running ahead of him. He drew a bead on the creature and fired. A feeling of power surged through him as the rat man screamed and died.

He ran on.

Minutes passed before he saw the second Oan. The furry beast died a flaming death without uttering a sound.

Ahead of him, Ro saw a clearing. Instinctively he swerved from his course to circle it. He had gone halfway around, when his eyes caught sight of a twisted, grey body perched on a limb overlooking the clearing. It was the rat man he sought—the one with the ray gun, crouching there, waiting for Ro to step unsuspectingly into the clearing.

Ro chuckled as he caught the Oan in his sights. He pulled the trigger. Fire seared from the muzzle of the gun.

The rat man screamed wildly. He crashed down from the tree, leaving a trail of broken limbs in his wake. His body struck the ground with a dull thud, thrashed hopelessly for a few seconds, then lay still.

Ro laughed aloud and stepped into the clearing. He was still laughing when the three Earthmen came upon the scene.

"You should have seen the fool," Ro said. "Perched up there, waiting for me. What kind of a woodsman did he think I was?"

He stooped and lifted the Oan's gun. His face grew grave as he did so. When he came erect, he was covering the white men.

"Hold your weapons above your heads," he ordered.

The Earthmen obeyed, puzzled frowns creasing their faces.

"Now back to the sphere," Ro instructed.

Marching in single file they returned to the metal ship. Ro signaled them to halt then and called to Na. She came into the clearing and stood at his side.

"All right, into the sphere. All of you."

"But why?" the professor protested. "What have we done? We're your friends."

"Do as I say," Ro shouted nervously. Then translated his words into the thoughts.

The professor obeyed, then Grimm. Carlson was the last to enter. Ro walked to the door behind him.

"Take these guns with you," he said, as the young Earthman entered the ship. "We will not need them here. My people will return to their homes now and all will be as it was."

"I understand," said Carlson. "There is no place for us here. We have brought nothing but trouble." He extended his hand. "I'm sorry."

Ro accepted the Earthman's gesture of friendship. He held the white hand in his firmly.

"You are a good friend," he said quietly. "Perhaps some day my people will grow up. Perhaps you will come again and we will meet you on equal terms. But now, our primitiveness, your science—there can be nothing but trouble. Make the others understand that. I will always remember you as friends. I wouldn't want our parting to be in anger."

"They will understand, Ro."

The Earthman closed the ship's door slowly.

Ro walked away from the sphere. He stood at the edge of the clearing, his arm about Na's shoulder, and watched the many colored fire spit from the rear of the ship. He and Na waved as the great mass of metal from another world left the ground. They waved until their white-skinned visitors had disappeared.

"Perhaps they will come again, when our people have grown up," Ro whispered sadly.

There was a hint of tears in his eyes.