At T.O.T. plus eight thousand three hours, the light experimental cruiser Oberlin dropped through a fold of superspace to take objective timespace fixes on the 23rd Island Universe as ail astrogation check � only to find, instead of the extra-galactic emptiness that never ceased to be horrifying to the most seasoned crew members, a Gaice battle wagon within a scant thirty thousand miles.

Fane, the watch officer, was at the controls, and in that moment of shock seven years of training paid off. As though slapping at an insect, his hard palm whacked back the switch he had just opened, reducing the mass of the Oberlin to that fractional part of an Earth-weight ounce expressed by one over three times ten to the ninth power.

The following fifteen minutes of violent nausea experienced by crew and the solitary passenger indicated that had Fane�s reflexes been slower by a hundredth of a second, the Oberlin would have sped on through superspace carrying its load of corpses until at last the weakest link in the drive devices failed.

The Oberlin fled through the roiled and viscid grayness that was in part a negation of objective reality, and in part that prosaic MVi factor so cleverly parenthesized in the Schenweiss equations.

The Oberlin carried Captain Luce, a commander who had acquired a certain lack of favor back in BuGalNav, two junior officers, Fane, who was seasoned, and Lorrity, who was not, three hardbitten enlisted technicians � Cantor, Simmins and Holzer � who were reliable because of their almost psychopathic lack of imagination, and Dr. Klaus Wasterno, a jolly Santa type possessed of a red face and the coldest blue eyes in Topographical Physics.

The cruiser itself was a projection of the third Schenweiss equation expressed in sixty-three alloys (seven of which were new), twelve families of plastics and four relatively inert elements whose gentle bombardments were so mingled that their basic animosity resulted in fusion and fission of an estimated ninety-three percent average efficiency. Built into this physical extension of a mathematical concept were those factors essential for the sustaining of life while the Oberlin moved from place to place through a gray timeless area which Schenweiss, for want of a better name, had termed �the half dimension�.

The seven of them gathered, at Luce�s order, in the small communal lounge, the only space on the ship that was not entirely functional.

Gray ghosts that wavered and droned as they fled through the incomprehensible. Gray faces and weakness and dismay.

�Out here!� Luce said. �Figure the odds. Just try to figure them!� He was a bull-necked man with a face ravaged by that most delicate vice, ambition.

�Release,� said Dr. Wasterno, �one grain of sand within the gravitational attraction of the Earth and compute the possibility of its striking squarely a second grain of sand, a specific second grain of sand in the Sahara. The odds would be the same. Is it important?�

�To me this happens,� Luce said. �To me! How much can a man stand?�

�To personalize it,� said Dr. Wasterno, �is as pointless as estimating the odds against its happening once it has happened.�

Luce glared at Wasterno. �What do you know about it? What do you know about luck? This was a last chance. You�re a civilian. This is our problem, doctor, but you, at this moment, are as inevitably dead as we are. Now there�ll be no return trip, no report on the twenty-third I. U. as a potential base against them.�

The two young officers had been looking at Luce and thinking of his reputation and thinking of how, as they achieved promotion, they would not make the mistakes that Luce had made. For a time they had forgotten death.

Simmins came back from the screen. He shrugged. �They picked it up okay, sir. Any time now, I�d say.�

�I didn�t ask for opinions, Simmins,� Luce snapped.

�I do not understand all this hopelessness,� Dr. Klaus Wasterno said, smiling nervously and automatically.

�There are no effective evasive actions we can take, that�s all,� Luce said. He turned to Fane. �Go snap us out and into any course you like, mister. It�ll give us time, but I don�t know what for.�

The six of them waited in the lounge. The wavering grayness vanished as though it had never been and reappeared in such a small fraction of a second that Lorrity, who had blinked at that moment, missed the tiny moment of reality.

Dr. Wasterno said, �But��

There was exaggerated patience in Captain Luce�s voice. �Over the past twelve years, doctor, probably forty of our light ships have been trapped by a Gaice heavy. You know that when heavy meets heavy on even terms, we have the edge. But we�ve never acquired or understood their ability to close with and destroy light craft in spite of all evasive action that can be taken. They can follow us in superspace and they are faster. If the fleeing ship stays in superspace the Gaice inevitably catches up. The only maneuver that is even partially effective is to cut out of superspace, take a new course and cut back in. During the interval of objectivity the Gaice flashes on by. They cut out as soon as they can and pick up the track again. But inevitably, one of two things has happened. No matter how random the maneuvers have been, the ship that flees will sooner or later drop out of super-space to find the Gaice within range and waiting, or our ship will change course, again at random, to find the Gaice, for all practical purposes, alongside. They have a knack of anticipation that we neither have nor understand. No ship has ever escaped once it was contacted too far from any of our fleets to run for cover In super-space. We are very obviously too far away to turn and run, If we stay in superspace they�ll have us in no less than twenty hours. If we dodge at random we can last a month, three months, even a year. If we attempt to establish a pattern in the evasive action, so that each successive maneuver takes us closer to home, they�ll get us in a week.�

�So!� said Dr. Wasterno softly.

�We�ll make it rough on �em, won�t we, sir?� Lorrity asked.

�Rough, mister? They don�t know the meaning of the word. They�re as immune to pleasure or unhappiness or any other human emotion as a � an annelid. And just as rational as an integral calculator. If you can say they think, in the way that we know the word, they are now thinking � here is an enemy ship. We have found it. We will chase it and we will kill them. Don�t assume they think of it as a sport, any more than an amoeba thinks of eating as sport.�

�All my life,� said Wasterno, �has been concerned with the location of a point in space. We are that point and now they practice my profession, eh?�

Luce ignored him. He turned to Lorrity. �Put the status report on the tape for instantaneous transmission and hook it up so it gets sent the next time we drop out.�

�Yes, sir,� said Lorrity. He licked his lips. He wondered who would tell Rita about him. He hoped that when that last moment came he wouldn�t scream.

Cantor took a greasy pack of cards from his coverall pocket and laid out a game of solitaire on the table-top. Luce put Holzer on the screen. Seven men waited for death. They did not meet each other�s eyes in the pervading grayness, in the subtle distortion of line and shadow of the half dimension. The red pips on Cantor�s cards were gray-black and the black pips were pale.

�It cannot be so,� Wasterno said softly. �It is something impossible that they do.� He found a paper and pencil and began to make computations. After an hour he moved back into his tiny personal cabin and closed the door.

At the end of four hundred hours the pursuit had become all there was of life. The dogged tenacity of it stretched nerves to a high, thin pitch. Once, when they dropped out of superspace the Gaice heavy appeared at the same instant, seventy thousand miles off the starboard bow, after having been off the screen for so long that false hopes had arisen. Had their estimate been better by half the pursuit would have ended in that same moment of incredulous recognition.

Dr. Klaus Wasterno went to Captain Luce in his quarters and said, �I must understand more clearly the mechanics of the changes in course.�

Luce propped himself up on one elbow. �Why?�

�Because I think I know what they do in that ship that follows us, captain. And if I know clearly what they do, then we can take a further step and they cannot catch us.�

�Stick to your arithmetic, doctor. I�m commanding this ship.�

Doctor Wasterno beamed jovially. �It occurred to me that certain appreciation would accrue to the first commander to successfully evade the Gaice when trapped.�

Luce was immobile for long seconds. �Have you got something?�

�First tell me one thing. While in superspace our course is irregular, but speed is constant. And I know that the course pattern for the superspace period is set in advance. But how is that done?�

�We assume superspace to be three-dimensional for the purpose of our evasive action. So we take one of the tapes and punch it at random with a stylus and feed it to the automatic pilot. As each hole in the random tape reaches the pilot beam light shines through onto the plate and sends us off in a random direction at a previously unknown angle. There is no chance of a pattern, you see.�

�This is a problem, captain, in infinities and also in the theory of randomness. I suspect your method is no good.�

Luce scowled.

�It was devised by some of your people, doctor.�

�It fails to work, thus it must be no good. That is a starting point. If we were dealing with a weak infinity, aleph sub zero, a number progression, they should catch us in minutes. For a stronger infinity, aleph sub one, such as the points within a cube, it should take them longer, but they should be able to solve the problem. But here we are dealing with the strongest infinity yet known, aleph sub two, the diversity of geometric forms, and if it were completely random they should never anticipate or catch us at all. Mathematically I can prove that it is impossible for them to catch us if the evasive tactics are random in the pure sense. Thus there is pattern. When we find the cause of the pattern, we know how to avoid making that pattern.�

�It�s definitely random,� Captain Luce said.

�Have you a record of what evasive action we have taken?�

�Certainly. On the automatic log, expressed in numerical terms. Angles and degrees from the established reference point � Sol.�

�I must look at those figures. And you must do one thing to give me time to learn what I must learn. Have three persons prepare the next tape. The first to punch not very many holes and the second more and the third to fill the tape.�

�That doesn�t make sense,� Luce objected.

�Captain, if you would just do it��

�All right, all right!�