CHAPTER 1
 Jonner's hand dropped to his pistol and he edged cautiously behind a big rock as another groundcar appeared among the dunes to the south and approached the little group of men. He was sure Sir Stanrich had told him there were to be four others in his little task force: and there were four with him now.
But the new groundcar did not approach like a hostile patrol car. There was an air of confidence about the way its driver swung it up to the others. Jonner held his hand, thinking furiously, as the airtight door swung open and the newcomer leaped lightly to the ground.
The sun was settling over the iron-red wastes of the Isidis Desert. The groundcars clustered like giant beetles at the top of the cliff that dropped straight down to the shadowed lowland of Syrtis Major. The six men in marsuits, huddled at rendezvous, kept their helmet radios low, for Mars City was less than fifty miles east of them.
With the twilight, the blue mist of Mars was beginning to settle toward the ground.
Jonner debated with himself. Could he have misunderstood Sir Stanrich? Or could the plans have been changed after he left the Isidis spaceport? No. Then who was the sixth man? And which man was he?
"Regina fell right after I left," said the burly, gray-haired man. That would be Tyruss, the former space captain, who had come here from Regina. "Our troops were falling back along the Hadriacum Lowland. I suppose they plan to make a stand before Charax."
"No, Charax is to be evacuated tonight," said Jonner, and savored the shock of that announcement on his hearers.
He studied the credentials each man had handed him on arrival. There was Tyruss, from Regina. There was Farlan, an astrogator from the Rebel defenses in the Strymon Canals, and there was Aron, who had just arrived, a space engineer from the Hadriacum front. There were Stein, an astrogator, and Wessfeld, an engineer, who had come together in one groundcar from Charax.
The credentials were all alike, except the names. But one of them was—must be—a Marscorp spy.
CHAPTER 2
 Jonner could not check with Sir Stanrich by radio—Mars City was too close, and they would be overheard. He had no time to spend investigating his personnel—Sir Stanrich had impressed on him that their mission must be carried out on schedule.
He decided he would not tell them just yet that one of them could not be trusted. He might be able to trip the spy. But he said:
"One or more of us may be killed or captured, so I'm going to brief everyone. No matter how many of us are lost, those who are left must carry out the mission. What were you told about this?"
"I was told to meet you here and follow your instructions. I was told it's a dangerous and important assignment. That's all," said Tyruss. The others murmured agreement.
"The instructions I give you won't be mine, but those of Sir Stanrich O'Kellin, supreme commander of the Rebel forces," said Jonner. He squatted on the sand and the others crowded around in the blue twilight as he sketched diagrams with his gloved hand while he talked:
"As some of you may have learned, the Charax Rebellion is in danger of collapsing, because our supplies have been running out since Marscorp intercepted and destroyed our last space fleet from Earth. Plan Red, which was our master plan for defeating Marscorp in the field by capturing the dome-cities one by one, has failed. Regina and Charax are being evacuated because we couldn't hold them much longer anyway, and all our people are being transported around the Marscorp territory to the secret underground spaceport we established in the Isidis Desert two years ago.
"This is a temporary measure, to prepare for Plan Blue, our last-gasp emergency plan. Marscorp will no doubt find the location of the underground base by observation of the refugees, but we hope to have Plan Blue in operation before they can shift their forces from Hadriacum to the desert and break through our defenses."
"I've heard rumors of this Plan Blue," said Farlan, a slight man with blond hair. "What is it?"
"I don't know," conceded Jonner candidly. "I don't think anyone does but Sir Stanrich and a few of our top strategists. But our part of it is this:
"You may not know it, but we lost our last G-boat when we pulled that unsuccessful attack on Phobos early this year. We do have an old spaceship, riding in a polar orbit, that Marscorp doesn't know about, but no way to get up to it. Our job is to capture a Marscorp G-boat, get to that spaceship, capture The Egg and tow it into an Earthward orbit."
"The Egg?" repeated Stein, a dark, chubby fellow. "You mean that ovoid space station of Marscorp's with the antennae sticking out all over it? I've seen that thing floating up there. I always wondered why we didn't blast it."
"Not important enough," said Jonner. "It's an experimental laboratory that amplifies the magnetic field of Mars, and they've been experimenting with it as an auxiliary power station. But neither side is bothered by any lack of power from the atomic energy sources on Mars."
Tyruss appeared annoyed at this.
"Tell me something, Jonner," he demanded. "If it wasn't important enough to blast when we had the ships to do it, why is it important enough for us to capture now?"
"I don't know," said Jonner. "Those are our orders. Now, we leave the groundcars here and go on foot to Marsport. Check equipment, everyone."
"Say," commented Farlan after a moment, "I don't seem to have any sunburn lotion."
"You can have mine," said Aron, laughing. "This far from the sun, I haven't been sunburned yet, and don't expect to be."
"Haven't been on Mars a year yet, have you?" suggested Tyruss.
"No," admitted Aron. "I came from Earth with the last space fleet and escaped in a lifeboat. Why?"
"There's an Earth-sun conjunction coming up. Every time the Earth swings between Mars and the sun, everybody on Mars gets a bad sunburn. When it comes, you better cover yourself with lotion, because clothes don't protect you and even if you're in a city, the domes and house roofs are transparent to pick up the sun's heat."
"We have enough among us," said Jonner. "Besides, if our mission goes off on schedule, we'll be back at base by the time the Earth-sun conjunction starts. Let's head for Marsport."
CHAPTER 3

The six men crouched in the concealing canal sage near the edge of Marsport, the spaceport outside Mars City. The blue mist was a heavy fog that swirled around them.
In the lighted circle of the spaceport area three stubby, two-stage gravity-boats sat upright, about a hundred yards apart. These were the heavy duty rockets that plied back and forth to Phobos, Mars' inner moon and Marscorp's natural space station, entering the planetary atmosphere of Mars where spaceships could not go. Workmen stirred busily around one of the G-boats; a guard stood at the entrance port of each of the other two.
Jonner tried to assess the evidence, to decide which of his five companions was the Marscorp spy. How Marscorp had found out about the expedition, how the credentials had been forged, how the rendezvous had been learned, did not matter now. Marscorp could not know their plans beyond the rendezvous in the desert, because only he and Sir Stanrich had known the orders Sir Stanrich had given him for this mission.
The fact that Stein and Wessfeld had arrived together from Charax eliminated them as suspects, for the Charax command would have known whether one or two men were to be sent from there.
Jonner did not believe Tyruss was the spy. Jonner had won his space papers just before the Rebellion began, but it was logical that Sir Stanrich would send a more experienced space captain to handle their ship.
That left Farlan and Aron, from different sections of the Hadriacum front. Which one? In their specialties, Farlan was an alternate to Stein as an astrogator, Aron an alternate to Wessfeld as an engineer. But every spaceman could handle every other spaceman's duties in an emergency, and it was hard to say which task they had decided to double up on.
Jonner expected the spy to make some move here, tonight, and he had prepared for it on the way from the desert. One earphone of his helmet receiver was tuned with his speaker to the Rebel band they used, the other was tuned to the local frequency used by Marscorp. Jonner listened with one ear to the occasional reports and orders that were passed around the spaceport.
Jonner punched Tyruss, next to him, twice on the shoulder. It was the signal. The six men rose and moved forward together.
The sentry who loomed before them had no chance. A heat-gun beam is invisible. They cut him down and scurried to the edge of the spaceport, into the circle of light, running in long leaps toward the nearest G-boat.
It was as they broke from the canal sage that the thing happened which Jonner had expected. The words were shouted into the earphone attuned to the Marscorp band: "Attention, Marscorp! Att...."
Jonner pressed a button on his belt, and his other defense went into action. A scrambler beam cut in on the attempted warning, and everything on that channel dissolved into a buzzing roar.
Jonner cast a glance down the line of his companions, but they were too far separated for him to see whether any of them was talking into his helmet microphone.
Some of the workmen at the far G-boat saw them running across the field, and scattered in alarm, but the scrambling prevented them from warning others through helmet communicators. The guard at the G-boat that was their goal saw them when they were fifty feet away. He was cut down as he tried to duck around the G-boat.
They ran up the ramp. Jonner, first to reach the port, stopped and tried to watch his companions as they hurried past him. Tyruss was fumbling at some control on the belt of his marsuit. His radio channel control?
Armed men were converging on the G-boat from all over the field as Jonner slammed and fastened the port. They scrambled up to the nose of the G-boat, and he and Tyruss sank into the pilots' seats.
"Strap down for blast-off!" shouted Jonner, and wished viciously that the spy would still be tuned on the Marscorp band and fail to hear him. But everyone strapped down, hurriedly.
A score of Marscorp soldiers were standing around the G-boat, firing up at its ports with heat-guns. The beams were futile, for G-boats were built to stand frictional temperatures it would take a heat-gun minutes to build to. Halfway across the field, a squad of men wheeled an anti-tank gun into position.
The gentle gravity of Mars quadrupled as the G-boat strained upward on roaring jets, gathering speed. Through the port, Jonner saw the anti-tank gun's muzzle elevate and blossom flame. There was no impact; and there was no opportunity for another shot.
The G-boat curved eastward in a long ascending arc. The first stage dropped off over the Aerian Desert, and in a few moments they were in free fall.
CHAPTER 4
 Jonner unstrapped and floated to each man in turn, examining his control belt. Farlan's channel dial was a fraction off the band they used.
"Farlan, your radio control's off center," said Jonner quietly.
"What?" said Farlan's voice, blurred a little. He fumbled at the dial, and his words came in clearly. "Must have hit it against something."
Or he could have missed a little when he returned the dial to channel after trying to warn Marscorp. But Tyruss had been fumbling with something on his belt as they ran onto the G-boat. No, it wouldn't do to make an accusation against the wrong man.
An automatic calendar on the G-boat's control board showed the date: upright, the Martian date, Aster 32, 24; reversed, the Earth date, June 1, 2020.
Jonner looked down through the port at the inhabited hemisphere of Mars unfolding below them. Those green lowlands, those red deserts, now were all in Marscorp hands—even the cradle of the Charax Rebellion, the dome-city of Charax, at the edge of the edge of the Tiphys Fretum Lowland in the south polar area.
There, six Martian years ago, the rebellion had flared bravely against the Mars Corporation. Marscorp had held a monopoly on space travel between Earth and Mars since the first Martian colony was established at Mars City in the Earth year 1985. For the supplies Marscorp brought from Earth, the price was kept high. Marscorp also was the OGM—the Official Government of Mars, or, as the colonists read the initials, "Old Greedy Marscorp"—and Marscorp made and enforced the laws.
It had been a fairly even match at first. Marscorp's initial monopoly of the supply lines had been overcome when many of the people on Earth were roused to sympathy for the Rebel cause. Gradually, the Rebels had invested much of the Hadriacum Lowland with its dome-farms and had captured Regina, another of the planet's six dome-cities.
That had been before the disastrous space battle of the year 23. Now, in the past year, the Rebels had been pushed back to the wall. All that was left to them was Plan Blue. And what was Plan Blue?
Jonner looked over his five companions. All helmets were off now, and Jonner couldn't detect a guilty look in any face. He had never seen such pure unanimity of apparent innocence and loyalty.
"Now that we're aspace, we'll go on the customary shifts," he said: "eight hours duty, eight hours sleep, eight hours free time. We'll pair off: Stein with Farlan, Wessfeld with Aron, Tyruss with me.
"And these are special orders: no one is to let the man with whom he is paired out of his sight."
He would not tell them more than that now; he hoped to trap the spy when they approached The Egg.
CHAPTER 5
 The spaceship slid up orbit, overtaking the shining ovoid from which antennae sprouted like pins from a pin-cushion. The captured G-boat was lashed to the spaceship's side.
"You'd think they'd have some defenses, anyhow," grumbled Tyruss, watching the ovoid on the screen.
"Why?" countered Jonner. "They knew we didn't have any G-boats left, and they didn't know we had any spaceships left, either. Of course, they don't know this is our target, but I'll bet they have some ships from Phobos on the way here now, anyhow."
Their timing was just right. Thirty minutes later The Egg would swing around the limb of Mars, in line of sight with Marsport. But so far there had been no chance for The Egg to receive a radio warning of the stolen G-boat.
The spaceship pulled abreast of The Egg and Jonner and Tyruss went across to it in spacesuits. They passed through the airlock to find The Egg's crew of three waiting with welcoming smiles. The smiles faded at the sight of their levelled heat-guns.
"Sorry you weren't expecting us," said Jonner, opening the face-plate of his spacesuit with his left hand. "You'll have to get into spacesuits."
They sent their captives through the airlock and across the intervening space to the spaceship, where the others would be awaiting them. Then Jonner and Tyruss searched The Egg for other Marscorp personnel. They found none.
"We'd better get a line on her and get under way before those ships from Phobos can get here," said Tyruss.
"Right," agreed Jonner, and they got busy.
A towline secured between the two vessels, Jonner and Tyruss returned to the spaceship. The three Marscorp captives had been secured by chains to stanchions on the storage deck, just above the engine deck. Stein and Farlan, the engineers, were standing by.
"We're getting under way," Tyruss told them.
Stein and Farlan descended to the engine deck, and Tyruss and Jonner climbed to the control deck. On the centerdeck, Aron and Wessfeld, the astrogators, were asleep.
Tyruss climbed into the control chair and switched the radio to the Marscorp band. A voice blared from the communicator:
"Marscorp calling The Egg. Marscorp calling The Egg. Come in, Egg. Can you hear us, Egg? Rebels captured G-boat here. Double alert. Marscorp calling...."
Tyruss switched it off, laughing.
"A little late," he commented.
"Yes," said Jonner. "Keep the receiver on that band, Tyruss, because we won't be hearing from our side. But, until we finish our mission, I'm going to disconnect the sending equipment."
Jonner floated to the other side of the control deck and moved around behind the control board. He was busy disconnecting wires, a few minutes later, when he heard an exclamation from Tyruss.
He peeked around the edge of the control board. The three Marscorp captives were floating up the companionway from below, heat-guns in their hands!
"Keep your hands off those controls, Reb," warned one of them. "This ship's staying right here."
"Wasn't there another one in this gang, Robbo?" asked another.
Tyruss twisted in his chair and reached for his heat-gun. One of the Marscorp men rayed him through the throat.
Cautiously, Jonner poked the muzzle of his heat-gun around the edge of the control board. Methodically, he shot the three Marscorp men, one by one. They died without discovering the source of the invisible heat-beam that cut them down.
Tyruss was dead. Cursing, Jonner went below, heat-gun in hand. On the centerdeck, Wessfeld's body floated. Wessfeld was dead, burned through the chest. Aron was not there.
He found all three of the others, locked in the airlock, without spacesuits. Jonner watched Aron suspiciously as they emerged.
"What happened?" he demanded of Aron.
"I don't know," disclaimed Aron. "They woke us up. They had heat-guns then. Wessfeld tried to reach his, and they shot him. Stein and Farlan were already in the airlock when they brought me down."
"Stein, were you and Farlan constantly in sight of each other, as ordered?" asked Jonner, watching Aron. Did Aron's eyes widen apprehensively?
Stein started.
"Why, no," he admitted. "Farlan was on the engine deck, and I was down in the airlock checking the spacesuits before blast-off. That's routine, you know. They herded Farlan down and caught me by surprise."
"That's right," said Farlan. "I was checking the engines when they came through the hatch from above with heat-guns."
"Damn!" exploded Jonner. "I gave everyone strict orders—all right, it's too late now. It just cost us two men, and one of the four of us left is a Marscorp spy. Everyone get above and strap down for acceleration."
The spy was Aron or Farlan, but he still didn't know which. Aron could have feigned sleep, and slipped down to the storage deck to release and arm the Marscorp men. Or Farlan could have climbed from the engine deck and done it while Stein was in the airlock. Whoever it was, he had chosen to be locked in with the others—probably in case the sortie failed.
Now they were two men short, and still he would have to pair off with Aron and pair Stein with Farlan. They would have to go on twelve-hour duty shifts, with only four hours free time.
And to what purpose? As Tyruss had suggested several times, why couldn't they have just blasted The Egg out of space, if the purpose was to get rid of it? Why go to all the trouble of shifting it to an Earthward orbit? The Earth would be nowhere near the intersection point when The Egg reached Earth's orbit, if that made any difference.
Jonner had at last let the others know, as he should have before, that one of them was a spy. But he would not tell them, as he had told Tyruss, that he had disconnected the radio transmitter. Let the spy try to get in touch with Marscorp now!
CHAPTER 6
 "Jonner," said Aron, "there are a couple of blips on the radar screen that shouldn't be there."
Jonner swung the control chair to look at the screen. There were two dots there, almost directly to the rear of the spaceship. Jonner watched them. They held their position on the screen.
"I don't know," he said. "Pretty large for meteors, and there doesn't seem to be any lateral movement."
Their ship had just begun acceleration, following a hyperbola that would break them free of Mars' gravity. It was a hyperbola that swung the ship against the direction of the planet's orbital travel, and, while speeding the ship away from the planet, slowed it in relation to the sun.
Jonner and Aron were on duty on the control deck. Stein and Farlan slept on the centerdeck below. Two 24-hour periods had passed since they captured The Egg and maneuvered it into the right orbit for their departure from the Martian area.
The blips grew on the screen, and still they did not move laterally.
"Spaceships," Jonner decided.
"They're following our course, and overtaking us."
"Marscorp ships!" exclaimed Aron. "But Jonner, we never were in radar range of any Marscorp ship or installation. How could they know our position and course?"
Without replying, Jonner arose from the control chair and went around behind the control board. The wires to the radio transmitter, which he had disconnected so carefully, had been reconnected.
"Aron," said Jonner, coming back to the control chair, "go down and chain Farlan to his bunk. He's our Marscorp spy."
"He is?" Aron's eyes widened. "How do you know?"
"Because you haven't been out of my sight since we took The Egg in tow, and you haven't been near that control board while we were on duty. Stein must have let Farlan get away from him again."
"Why not Stein?"
"You forget. Stein and Wessfeld arrived together from Charax, at the rendezvous. They had to be clean."
Aron unstrapped and arose.
"Shouldn't we boost acceleration and try to evade them?" he asked, gesturing at the radar screen.
"We can't now," said Jonner. "We're on an escape hyperbola and we've got to hold this acceleration until she runs out, or we'd throw it completely off."
Aron went below. Jonner watched the screen anxiously. The Marscorp ships must have set an interception course, for their acceleration was much too high to be following their own escape orbit. They were getting closer rapidly.
Jonner looked at the chronometer and at the tape still ticking through the ship's control mechanism. Eleven minutes was a brief time, but it seemed long when enemy ships were overtaking them at twice their acceleration.
Towing The Egg, this old ship could not match the Marscorp attackers' acceleration. It could accelerate much faster than it was, but if he was to hit the Earthward orbit he had been ordered to take he would have to hold his present acceleration until the eleven minutes was up.
And the Marscorp ships got closer by the minute.
CHAPTER 7
 Aron climbed back to the control deck from below.
"Farlan's tied up, and he's madder than hell," Aron reported. "Stein said Farlan did go behind the control board on their last duty stretch, to 'adjust' the radio. What's the situation now?"
"They've started decelerating to match our pace when they get abreast of us," said Jonner, indicating the rocket flares that now appeared on the aft visual screen.
The tape suddenly ran out, and the rockets' roar faded. They were in free fall again.
"Get into a spacesuit and cut that towline," commanded Jonner. "We're going to make a run for it."
"We're not going to stay and guard The Egg?" asked Aron, getting a suit off one of the hooks.
"No outside guns. This hulk was a supply ship. As soon as you get back in and secure the outer airlock, holler and we'll start partial acceleration. When you've strapped down somewhere below, holler again and we'll blow the tubes."
While Aron went below to carry out his assignment, Jonner swung the ship end-to with the gyroscopes. He prayed silently that the towline to The Egg wouldn't foul. They'd have to head back toward Mars, for further acceleration in this direction would throw them, helpless, in a path toward outer space.
The radio loudspeaker boomed:
"OGM ship Phobos-29 to Rebel spaceship. Stand by for boarding or get blasted."
The Marscorp ships were within a few miles now, slowing to match the pace of the Rebel ship.
The outer airlock warning light flashed red, then green again.
"Ready!" said Aron's voice on the ship's communicator.
Jonner flicked his radio transmitter to the Marscorp beam.
"Go to hell!" he announced, and depressed the firing buttons.
 
CHAPTER 8
 It was uncomfortable for Aron, climbing out of the airlock, but Jonner threw the ship into a full G acceleration. The Marscorp ships loomed suddenly to each side, then faded behind them. A few futile flashes of gunfire blossomed from their noses. Then rings of fire appeared behind them as they gave chase.
"Strapped down!" called Aron, and Jonner gave the rockets full blast.
The ship leaped like a frantic old war-horse. Jonner was pressed down heavily in his control chair. Its beams and plates groaned as G was piled on G.
The Egg was gone from the rearward screens, released and floating free in an Earthward orbit. The Marscorp ships fell farther behind. Then they stopped receding and began to grow on the screens again. Newer and more powerful, they were overtaking the Rebel ship.
Suddenly the ship's rockets ceased firing again, and they were in free fall. A moment later, Aron popped up from below.
"Are we hit?" he asked.
"No, they aren't back in range yet," answered Jonner. "We're out of fuel. Maybe it's just as well they came along, because I don't believe this clunk had enough fuel to overtake Mars again, even if we hadn't blown it in that escape try."
The Marscorp attackers apparently interpreted the Rebel ship's dead rocket tubes as a surrender. Within half an hour they had drawn alongside, and armed men in spacesuits came through the airlock. Farlan was freed of his chains, and Jonner, Stein and Aron were herded onto the centerdeck of one of the Marscorp ships and secured to stanchions.
The Marscorp captain floated before them, looking them over quizzically.
"I don't know what you fellows were trying to prove, but you're lucky," he said. "If you hadn't cut your rockets when you did, we'd have blasted you out of space."
Jonner answered out of the knowledge that no ships which had accelerated as these two had in the past hour would have more than enough fuel left to get them back to Phobos. The Egg, trailing far behind Mars now, would overtake the planet gradually as the pull of the sun sped it up, but it would pass Mars well to sunward in its plunge toward the orbit of Earth. Any ship that tried to intercept it from Mars now would fight increasing solar gravity and would run the risk of not getting back to Mars.
"Well, we accomplished our mission, anyhow," Jonner said resignedly, "for whatever it's worth."
"A fool's mission," said the Marscorp captain, and Jonner was inclined to agree with him. "The Egg was an experimental laboratory and an auxiliary power station, and we can build another cheaper than we could recover it. As for you fellows, you're better off than you realize."
"How's that?" asked Stein.
"Why, if you aren't tried as war criminals, you ought to be freed pretty quickly. According to the latest news reports from Mars City, our armies are driving your people back into your underground base in the Isidis Desert. The war will be over as soon as we've cracked that."
CHAPTER 9
 Jonner, Stein and Aron lay around in the Marscorp brig on Phobos for more than a month. To be precise, they floated around, for Phobos had little more surface gravity than a spaceship in orbit. When there was no indication they were going to be transferred from Phobos, Jonner set up a howl that at last was heard in the little moon's officialdom.
Jonner was taken before the adjutant of the Phobos base to air his complaint.
"Look," said Jonner, placing both hands belligerently on the official's desk, "the terms of the terrestrial Space Compact apply to Mars, too. No prisoners of war shall be confined beyond a planetary atmosphere, except for so long as it is impracticable for them to be transferred to a surface prison."
"That provision was written into the compact to permit inspection by neutral powers and because, ordinarily, a prisoner has some hope that a surface prison will be overrun by troops of his own side and he will be released," answered the adjutant mildly, peering at Jonner over old-fashioned rimless spectacles. "In your case, that's not likely to happen and I can't see why you're raising such a fuss. The last we heard up here, our troops were about to overrun your last base."
"What do you mean, the last you heard?" demanded Jonner. "I heard that two days before we were brought to Phobos."
"Radio communication with Mars has been out completely," explained the adjutant good-naturedly. "Static's always bad during the Earth-sun conjunctions, as you ought to know, being a spaceman. This time we haven't been able to get anything through at all."
"Well, maybe it's true that we've lost and the war's about over," said Jonner. "But the three of us still want to be transferred to the surface. Free fall can drive you nuts when you're in an eight-by-eight cell."
"As a matter of fact," said the adjutant, "there hasn't been any G-boat traffic to and from the surface since the radio went out. It's a dangerous business, trying to land at a spaceport without any radio guide. But we have to send a G-boat down for supplies in a couple of days, and if you fellows are insistent about it, we'll send you down to Marsport on it."
It was not two days, but more than a week later that the three of them were allowed to get into spacesuits and were escorted out to a G-boat anchored to the surface of Phobos.
Above them, the orange disc of Mars filled the sky. Phobos was swinging across the inhabited hemisphere now, and the dark green areas of Syrtis and Hadriacum were plainly visible.
Jonner strained his eyes upward at the red spot that was the Isidis Desert. Somewhere in the heart of that red spot, Sir Stanrich O'Kellin was directing the last-gasp stand of the Charax Rebels. They would be manning the underground chambers of the base, perhaps fighting in the corridors as the Marscorp troops battled to effect an entry.
It might even be that the base had fallen by now, overrun by the government forces, and he and his companions would be, technically, free men by the time they landed at Marsport. Jonner sighed unhappily. He didn't want that kind of freedom.
Following Stein and Aron, he climbed into the G-boat. It had a crew of two, plus an armed guard for the prisoners.
"There'll be no unstrapping during free fall," announced the G-boat pilot. "Everybody will remain strapped down until we land. With the Earth-sun conjunction over, we've re-established radio communication partially, but it's spotty, and we may crash."
"Is the war over?" asked Jonner.
"How the hell should I know?" grunted the pilot. "We haven't had a single news broadcast that makes sense since the radio came back in. They're all chopped up with static."
The G-boat lifted gently from the surface of Phobos and began its spiral downward toward Mars. The six men, crowded together in its single passenger compartment, listened to the radio that spat and growled over their heads.
What they heard was unintelligible.
"Sector Four ... squawk ... spsst!" snarled the loudspeaker. "Colonel ... squawk ... troops in ... squawk ... move tank squad to ... spsst-crack-crack!... more ambulances ... squawk ... ninety per cent disabled...."
Periodically the pilot tried to establish contact:
"G-boat MC-20 to Marsport. G-boat MC-20 to Marsport. Come in, Marsport."
The attempts were futile until the G-boat had entered the atmosphere and was gliding high above the desert on its broad wings. Then, miraculously, the airwaves were clear for a moment.
"Marsport to G-boat MC-20," said the loudspeaker. "Go ahead."
"G-boat MC-20 to Marsport," said the pilot hurriedly. "Give us a beam. We're coming in for a landing."
"Don't land! We're...!" exclaimed the loudspeaker, and exploded into static in midsentence.
"What the hell do they mean, don't land?" snorted the pilot, fiddling frantically and uselessly with dials. "They think I've got enough fuel to get back to Phobos?"
The G-boat held its glide and swooped down on Marsport, a tiny landing field and a miniature group of buildings set apart from the dome of Mars City. Groups of men were scurrying about at the port like ants. A column of smoke rose ominously from one of the buildings.
The G-boat touched ground and skidded to a stop in mid-field. Its passengers unstrapped and the pilot opened the port.
Men crowded into the G-boat, men with drawn heat-guns, men in the blue-and-gold marsuits of the Charax Rebels!
CHAPTER 10
 Jonner, a free man again, rode into Mars City in a groundcar with Sir Stanrich O'Kellin. Stein and Aron had remained at Marsport for the time being. Marsport was completely in the hands of the Rebels, and efforts were being made to get through by radio to Phobos to give the Marscorp forces there a surrender ultimatum.
"What's happened to the Mars City dome?" asked Jonner in astonishment as they approached the city. The once-transparent dome was cracked and badly discolored.
"Plan Blue," answered Sir Stanrich with a smile.
"Look, sir, how about telling me what happened?" said Jonner. "When we got captured in the middle of our wild goose chase with Marscorp's Egg, our troops had been driven into the ground at the Isidis base and we got the impression it was only a matter of time before that fell. Then the radio goes out for a few days and we land here to find Mars City overrun with our troops."
"Why," said Sir Stanrich, his mustache quirking mischievously, "we counter-attacked. We came out of the base, defeated the Marscorp army there, drove across the desert to Mars City and took it. Task forces are out now, taking over the other cities. That's all there is to it."
"Simple!" snorted Jonner. "Except that they outnumbered us four or five to one, and probably outgunned us more than that."
"Science wins wars now; my boy, not numbers and guns."
They had entered the Mars City airlock and were driving down the broad Avenue of the Canals. Rebel soldiers swarmed through the city. The few men and women they saw in Marscorp uniforms staggered around, groping blindly, their faces and arms fiery red and peeling from sunburn.
"You'll get a medal out of it, too," commented Sir Stanrich.
"Why? Why me?"
"Because you followed orders, even though your mission appeared useless. It was your 'wild goose chase' that made our victory possible.
"You see, only the blue mist of Mars protects its surface from the hard rays of the sun. Without it, we'd have no more protection than a naked man in space. The reason we're in for a bad sunburn every year is that the blue mist dissipates partially at every Earth-sun conjunction."
"But what would The Egg have to do with that?" asked Jonner.
"The Egg amplifies the effect of magnetic fields, the way a lens concentrates light rays," answered Sir Stanrich. "It's the Earth's magnetic field, not that of Mars, that interferes with the blue mist every time the Earth passes between Mars and the sun. And to amplify Earth's magnetic field, we had to place The Egg directly between Mars and Earth during the Earth-sun conjunction—and you put it there when you got the Egg into an Earthward orbit on schedule."
"But, Sir Stanrich, I've been sunburned a dozen times at these conjunctions...."
"Not like this. When the blue mist was stripped away completely this time, everyone on the surface was affected. Marscorp's troops were put out of action as an effective fighting force when they received severe burns over most of their bodies and were afflicted with acute conjunctivitis so badly they were half blinded. That's why we abandoned Charax and Regina and pulled all our people to the Isidis base while the conjunction was under way, we were all protected from the sun ... underground!"
They had reached the center of the city. Above the old Syrtis Major Hotel, which had served as Marscorp's supreme headquarters, the flag of the Charax Rebels was fluttering in the breeze from the city's air circulators.
Marscorp was beaten. Mars was free.

The End