“Never overestimate the intelligence of a computer. You forget that it is a machine with zero imagination. Now, let me see if this will do us any good.” He punched keys rapidly, then muttered a curse and kicked the console. “No good. We will have to run nine to the tenth power numbers and, at seven hundred a second, it will take us about five months to do them all.”

  “And we have just three weeks left.”

  “I can still read a calendar, thank you, Meta. But we’ll have to try in any case. Send alternate numbers from one up and counting from 9,999,999,999 back down. Then we’ll get the navy code department to give us all their signals to send as well; one of them might fit. The odds are still about five to one against hitting the right combination, but that is better than no odds at all. And we’ll keep working to see what else we can think of.”

  The navy sent over a small man named Shrenkly, who brought a large case of records. He was head of the code department, and a cipher and puzzle enthusiast as well. This was the greatest challenge of his long and undistinguished career. He hurled himself into the work with growing enthusiasm.

  “Wonderful opportunity, wonderful. The ascending and descending series are going out steadily. In the meantime I am taping permutations and substitutions of signals which will—”

  “That’s fine, keep at it,” Jason said, smiling enthusiastically and patting the man on the back. “I’ll get a report from you later, but right now we have a meeting to attend. Kerk, Meta, time to go.”

  “What meeting?” Meta asked as he tried to get her through the door.

  “The meeting I just made up to get away from that monomaniacal enthusiast,” he said when he finally got her into the corridor. “Let him do his job while we see if we can find another way in.”

  “I think what he has to say is very interesting.”

  “Fine, you talk to him—but not while I am around. Let us now spur our brains into action and see what we can come up with.”

  What they came up with was a number of ideas of varying quality but uniform record of failure. There was the miniature-flying-robot fiasco, where smaller and smaller robots were sent and blasted out of existence, right down to the smallest, about the size of a small coin. Obsessed by miniaturization, they constructed a flying-eye apparatus no larger than the head of a pin. It dragged a threadlike control wire after it that also supplied current for the infinitesimal ion drive. This device sparked and sizzled its way to within fifteen kilometers of the Indestructible before the sensors detected it and neatly blasted it out of existence with a single shot.

  There were other suggestions and brilliant plans, but none of them worked out in practice. The great ship floated serenely in space, reading seven hundred numbers a second and, in its spare time, blowing into fine dust any object that approached it. Each attempt took time; the days drifted by steadily. Jason was beginning to have a chronic headache and had difficulty sleeping. The problem seemed insoluble. He was feeding figures about destruction distances into the computer when Meta looked in on him.

  “I’ll be with Shrenkly if you need me,” she said.

  “Wonderful news.”

  “He taught me about frequency tables yesterday, and today he is going to start me on simple substitution ciphers.”

  “How thrilling.”

  “Well, it is to me. I’ve never done anything like this before. And it has some value: we are sending signals and one of them could be the correct one. It certainly is accomplishing more than you are with all your flying rocks. And there are only two days to go, too.”

  She stalked out and slammed the door. Jason slumped with fatigue, aware that failure was hovering close. He was pouring himself a huge glass of Old Fatigue Killer when Kerk came in.

  “Two days to go,” Kerk said.

  “Thanks. I wouldn’t have known if you hadn’t told me. I

  am well aware that a Pyrran never gives up, but I am getting the sneaking suspicion that we are licked.”

  “We are not beaten yet. We can fight.”

  “A very Pyrran answer—but it won’t work this time. We just can’t barge in there in battle armor and shoot the place up.”

  “Why not? Small-arms fire would just bounce off of us—as well as the low-powered rays. All we have to do is dodge the big stuff and bull through.”

  “That’s all! Do you have any idea how we are going to arrange that?”

  “No. But you will figure something out. And you better hurry.”

  “I know, two days. I suppose it’s easier to die than admit failure. We suit up, fly at the battleship behind a fleet of rocks that are blasted by the heavy stuff. Then we tell the enemy discrimination circuits that we are not armored space suits at all, but just a couple of jettisoned plastic beer barrels that they can shoot up with the small caliber stuff. Which then bounces off us like hail and we land inside and get a billion credits and live happily ever after.”

  “That’s the sort of thing. I’ll go and get the suits ready.”

  “Before you do that, just consider one thing in this preposterous plan. How do we tell the discrimination circuitry …” Jason’s voice ran down in mid sentence, and his eyes opened wide—then he clapped Kerk on the back. Heavily too, he was so excited, but the Pyrran seemed completely unaware of the blow.

  “That’s it, that’s how we do it!” Jason chortled, rushing to the computer console. Kerk waited patiently while Jason fed in figures and muttered over the pages of information that poured from the printer. The answer was not long in coming.

  “Here it is!” Jason held up a sheet. “The plan of attack— and it’s going to work. It is just a matter of remembering that the computer on that battleship is just a big dumb answering

  machine that counts on its fingers. But it does it very fast. It always performs in the same manner because it is programmed to do so. So here is what happens. Because of the main drive tubes the area with the least concentration of fire power is dead astern. Only one hundred and fourteen gun turrets can be trained that way. Their slew time varies.”

  “Slew time?”

  “The time it takes a turret to rotate one hundred and eighty degrees in azimuth. The small ones do it in less than a second. This is one factor. Other factors are which targets get that attention. Fastest-moving rocks get blasted first, even if they are farther away than a larger, slower-moving target. There are other factors like rate of fire, angle of depression of guns, and so forth. Our computer has chomped everything up and come up with this!”

  “What does it reveal?”

  “That we can make it. We will be in the center of a disk of flying rocks that will be aimed at the rear of the Indestructible. There will be a lot of rock, enough to keep all the guns busy that can bear on the spot. Our suits will be half the size of the smallest boulder. We will all be going at the same speed, in the same direction, so we should get the small-caliber stuff. Now, another cloud of rock, real heavy stuff, will converge on the stern of the ship from a ninety-degree angle, but it will not hit the two-hundred-kilometer limit until after the guns start blasting at us. The computer will track it and as soon as our wave is blasted will slew the big guns to get rid of the heavy stuff. As soon as these fire, we accelerate toward the stern tubes. We will then become prime targets, but, before the big guns can slew back, we should be inside the tubes.”

  “It sounds possible. What is the time gap between the instant we reach the tubes and the earliest the guns can fire?”

  “We leave their cone of fire exactly six-tenths of a second before they can blast us.”

  “Plenty of time. Let us go.”

  Jason held up his hand. “Just one thing. I’m game if you are. We carry cutting equipment and weapons. Once inside the ship there should not be too many problems. But it is not going to be that easy. I say that the two of us go. If we don’t tell Meta she will stay here.”

  “Three have a better chance than two to get through.”

  “And two have a better chance than one. I’m not going unless you agree.”

  “Agreed. Set the plan up.”

  Meta was busy with her newfound interest in codes and ciphers; it was a perfect time. The Earth navy ships were well trained in precision rock-throwing—as well as being completely bored by it. They let the computers do most of the work. While the preparations were being made, Kerk and Jason suited up in the combat suits: more tanks than suits, heavy with armor and slung about with weapons. Kerk attached the special equipment they would need while Jason short-circuited the airlock indicator so that Meta, in the control room, would not know they had left the ship. Silently they slipped out.

  No matter how many times you do it, no matter how you prepare yourself mentally, the sensation of floating free in space is not an enjoyable one. It is easy to lose orientation, to have the sensation that all directions are up—or down. Jason was more than slightly glad of the accompanying bulk of the Pyrran.

  “Operation has begun.”

  The voice crackled in their earphones; then they were too busy to be concerned about anything else. The computer informed them that the wall of giant boulders was sweeping toward them—they could see nothing themselves—and gave them instructions to pull aside. Then the things were suddenly there, floating ponderously by, already shrinking into the distance as the jets on the space suits fired. Again following instructions, they accelerated to the correct moving spot in

  space and fitted themselves into the gap in the center of the floating rock field. They had to juggle their jets until they had the same velocity as the boulders. Then, power cut off, they floated free.

  “Do you remember the instructions?” Jason asked.

  “Perfectly.”

  “Well, let me run through them again for the sake of my morale, if you don’t mind.” The battleship was visible now far ahead, a tiny splinter in space. “We do nothing at all to draw attention as we come in. There will be plenty of activity around us, but we don’t use power except in an extreme emergency. And when we get hit by small-caliber fire—it will be the best thing that can happen to us. Because it will mean the big guns will be firing at something else. Meanwhile the other attack of flying rocks will be coming in from our flank. We won’t see them—but our computer will. It is monitoring the battleship as well. Then the instant the big guns are on the second wave, it will send us the signal go. Then we go. Under full power toward the main drive tube. When our suit radar says we are eleven hundred meters from the ship, we put on full reverse thrust because we will be out of reach of the guns. See you at the bottom of the tube.”

  “What if the computer fires the tube to clear us out?”

  “I have been trying not to think about that. We can only hope that it is not programmed for such a complex action and that its logic circuits will not come up with the answer …”

  Space around them exploded with searing light. Their helmet visors darkened automatically, but the explosions could still be clearly seen, they were so intense. And silent. A rock the size of a small house fumed and vaporized soundlessly not a hundred meters from Jason, and he cringed inside the suit. The silent destruction continued—but the silence was suddenly shattered by deafening explosions. His suit vibrated with the impacts.

  He was being hit! Even though he had expected it, wanted

  it, the jarring was intense and unbelievably loud. Then it stopped as suddenly as it had begun, and dimly, he heard a weak voice say go.

  “Blast, Kerk, blast!” he shouted as he jammed on full power.

  The suit kicked him hard, numbing him, slowing his fingers as they grappled for the intensity control on the helmet and turned it off. He winced against the glare of burning matter but could just make out the disk of the spaceship’s stern before him, the main tube staring like a great black eye. It grew quickly until it filled space, and the sudden red glow of the present radar said he had passed the eleven-hundred-meter mark. The guns couldn’t touch him here—but he could crash into the battleship and demolish himself. Then the full blast of the retrojets hit him, slamming him against the suit, stunning him again. Control was impossible. The dark opening blossomed before him, filling his vision, blacking out everything else.

  He was inside it, the pressure lessening as the landing circuits took over and slowed his rate of descent. Had Kerk made it? He had stopped, floating free, when something plummeted from above, glanced off him, and crashed heavily into the end of the tube.

  “Kerk!” Jason grabbed the limp figure as it rebounded after the tremendous impact, grappled it, and turned his lights on it. “Kerk!” No answer. Dead?

  “Landed … faster than I intended.”

  “You did indeed. But we’re here. Now let’s get to work before the computer decides to burn us out.”

  Spurred by this danger, they unshipped the molecular un-binder torch, the only thing that would affect the tough tube liners, and worked a circular line on the wall just above the injectors. It took almost two minutes of painstaking work to slowly cut the opening, and every second of the time they waited for the tube to fire.

  It did not. The circle was completed, and Kerk put his shoulder to it and fired his jets. The plug of metal and the Pyrran instantly vanished from sight. Jason dived in right behind him, into the immense, brightly lit engine room.

  Made suddenly brighter by a flare of light behind him. Jason spun about just as the flames cut off. It had been a microsecond blast. “A smart computer,” he said weakly. “Smart indeed.”

  Kerk had ignored the blast and dived into a control room to one side. Jason followed him, met him as he emerged with a large chart in a twisted metal frame.

  “Diagram of the ship. Tore it from the wall. Central control this way. Go.”

  “All right, all right,” Jason muttered, working to keep pace with the Pyrran’s hustling form. This was what Pyrrans did best; it was an effort to keep up the pace.

  “Repair robots,” he said when they entered a long corridor, pointing to the tall, metal forms. “They won’t bother us …”

  Before he had finished speaking, the two robots had raised their welding torches and rushed to the attack. But the instant that they moved, Kerk’s gun blasted twice, blowing them into instant junk.

  “The ship’s computer is too smart. It will turn anything against us. Stay alert and cover my back.”

  There was no more time for talking. They changed their course often, so it would not be obvious that they were heading toward cent control. Every machine along the way wanted to destroy them. Housekeeping robots rushed at them with brooms, TV screens exploded as they passed, airtight doors tried to close on them. The suddenly electrified floors arced and sputtered. It was a battle, but a one-sided one as long as they stayed alert. Their suits were invulnerable to small-scale attack and well insulated from electricity. In the end they came to a door marked centra kontrolo. Kerk offhandedly

  blasted it open and floated through. The lights were lit, the room and the controls were spotlessly clean.

  “We’ve done it,” Jason said, looking at the pressure gauge, then cracking his helmet and smelling the cool air. “One billion credits. We’ve licked this bucket of bolts…”

  “THIS IS A FINAL WARNING,” the voice boomed, and their guns nosed about for the source before they realized it was just a recording. “THIS BATTLESHIP HAS BEEN ENTERED BY ILLEGAL MEANS. YOU ARE ORDERED TO LEAVE WITHIN THE NEXT FIFTEEN SECONDS OR THE ENTIRE SHIP WILL BE DESTROYED. CHARGES HAVE BEEN SET TO ASSURE THIS BATTLESHIP DOES NOT FALL INTO ENEMY HANDS. FOURTEEN …”

  “We can’t get out in time!” Jason shouted.

  “Shoot up the controls!”

  “No! The destruction controls won’t be here.”

  “TWELVE—”

  “What can we do?”

  “Nothing! Absolutely nothing at all … !”

  “EIGHT—”

  They looked at each other wordlessly. Jason put out his armored hand and Kerk touched it with his own.

  “SEVEN—”

  “Well, goodbye,” Jason said, and tried to smile.

  “FOUR … errrk. THR—”

  There was silence; then the mechanical voice spoke again, a quieter voice. “De-mothballing activated. Defenses disarmed. Am awaiting instructions.”

  “What … happened?” Jason asked.

  “De-mothballing signal received. Am awaiting instructions.”

  “Just in time,” Jason said, swallowing with some difficulty. “Just in time.” He fumbled with the unfamiliar controls until he finally turned on the communicator. Meta’s face glared from the screen at him.

  “Is that where you got to! You should not have gone without me and I shall never forgive you.”

  “I couldn’t take you,” Jason said. “I wouldn’t have gone myself if you had insisted. You are worth more than a billion credits to me.”

  “That’s the nicest thing you ever said to me.” She smiled now and blew him a kiss. Kerk grunted and looked on with great disinterest.

  “When you are through, would you tell us what happened?” he said. “Did the computer hit the right number?”

  “Not at all. I did it.” She smiled into the shocked silence. “I told you how interested I am now in codes and ciphers. Simply thrilling, with many military applications, too, of course. Shrenkly told me about substitution ciphers and I tried one, the most simple. Where the letter A is one, B is two and so forth. Next I put a word into this cipher but it came out 81122021, which was two numbers short. Then Shrenkly told me that there must be two digits for each letter or there would be transcription problems, like you have to use 01 for A instead of just the number. So I added a zero to the two one-digit numbers, and that made ten digits. Then I fed the number into the computer and it was sent and that was that.”

  “The jackpot with your first number—with your first try?” Jason asked hollowly. “Wasn’t that pretty lucky?”

  “Not really. You know military people don’t have much imagination. You must have told me that a thousand times at least. So I took the simplest possible, looked it up in the Esperanto dictionary …”

  “Haltu?”