It would have been the end of Lucky if he and Mindes had been on Earth.

Lucky had not missed the gathering madness in Mindes's voice. He had been waiting carefully for some break, some action to suit the violence of the engineer's hard-breathed sentences. Yet he had not entirely expected an outright assault with the blaster.

When Mindes's hand flashed to his holster, Lucky leaped to one side. On Earth, that movement would have come too late.

On Mercury, however, matters were different. Mercury's gravity was two fifths that of Earth, and Lucky's contracting muscles threw his abnormally light body (even including the suit he wore) farther to one side. Mindes, unaccustomed to low gravity, stumbled as he turned too quickly in order that his blaster might follow Lucky's motion.

The blaster's energy, therefore, struck bare ground, inches from Lucky's sinking body. It gouged a foot-deeo hole into the frigid rock.

Before Mindes could recover and aim again, Bigman had struck him at the end of a long, iow tackle carried through with the natural grace of a born Martian accustomed to low gravity.

Mindes went down. He shrieked wordlessly and then was silent, whether unconscious as the result of the fall or as the climax of his fevered emotions could not be told.

Bigman did not believe either possibility. "He's shamming," he cried passionately. "The dirty cobber is playing dead." He had wrenched the blaster from the fallen engineer's unresisting grip, and now he pointed it at the man's head.

Lucky said sharply, "None of that, Bigman."

Bigman hesitated. "He tried to kill you, Lucky." It was obvious that the little Martian would not have been half as angry if it had merely been himself who had been in danger of death. Yet he backed away.

Lucky was on his knees examining Mindes's face through the face-plate, shining his helmet light onto the other's pale, drawn features. He checked the pressure gauge of Mindes's suit, making sure the shock, of the fall had not loosened any of its joints. Then, seizing the fallen figure by a wrist and ankle, he slung it across his shoulders and rose to his feet.

"Back to the Dome," he said, "and, I'm afraid, to a' problem that's a little more complicated than the Chief thinks."

Bigman granted and followed Lucky's long stride closely, his own smaller build forcing him into a gravity-lengthened half trot. He kept his blaster ready, maneuvering his position to enable him, in case of need, to strike at Mindes without blasting down Lucky.

The "Chief was Hector Conway, head of the Council of Science. At more informal times he was called Uncle Hector by Lucky, since it was Hector Conway, along with Augustus Henree, who were the guardians of the young Lucky after the death of Lucky's parents as the result of a pirate attack near the orbit of Venus.

A week earlier Conway had said to Lucky with a casual air, almost as though he were offering him a vacation, "How would you like to go to Mercury, Lucky?"

"What's up, Uncle Hector?" asked Lucky.

"Nothing really," said Conway, frowning, "except some cheap politics. We're supporting a rather expensive project up at Mercury, one of those basic research things that may come to nothing, you know, and, on the other hand, may turn out to be quite revolutionary. It's a gamble. All those things are."

Lucky said, "Is it anything I know about?"

"I don't think so. It's quite recent. Anyway, Senator Swenson has pounced on it as an example of how the Council wastes taxpayers' money. You know the line. He's pressing for an investigation, and one of his boys went out to Mercury some months ago."

"Senator Swenson? I see." Lucky nodded. This was nothing new. The Council of Science over the past decades had slowly come to the fore of the fight against the dangers to Earth from both within and without the Solar System. In this age of Galactic civilization, with humanity spread through all the planets of all the stars in the Milky Way, only scientists could properly cope with mankind's problems. In fact, only the specially trained scientists of the Council were adequate.

Yet there were some men of Earth's government who feared the growing power of this Council of Science and others who used this suspicion to further their own ambitions. Senator Swenson was the foremost of the latter group. His attacks, usually directed against the Council's "wasteful" way of supporting research, were making him famous.

Lucky said, "Who's the man in charge of the project on Mercury? Anyone I know?"

"It's called Project Light, by the way. And the man in charge is an engineer named Scott Mindes. A bright boy, but he's not the man to handle this. The most embarrassing thing is that since Swenson kicked up this fuss all sorts of things have been going wrong with Project Light."

"I'll look into it if you wish, Uncle Hector."

"Good. The accidents and bad breaks are nothing, I'm sure, but we don't want Swenson. to maneuver us into some bad-looking spot. See what he's up to. And watch out for that man of his. Urteil is his name and he has a reputation of being a capable and dangerous fellow."

So that was all it started out as. Just a bit of investigation to forestall political difficulties. Nothing more.

Lucky landed on Mercury's North Pole expecting nothing more, and in two hours found himself at the wrong end of a. blaster bolt.

Lucky thought as he slogged back to the Dome with Mindes over his shoulders: There's more than just a bit of politics here.

Dr. Karl Gardoma stepped out of the small hospital room and faced Lucky and Bigman somberly. He was wiping his strong hands on a pad of fluffy plastosorb, which he tossed into the disposal unit when he finished. His dark-complexioned face, almost brown, was disturbed, his heavy eyebrows lowering. Even his black hair, cut close so that it stood up stiffly in thick array, seemed to accentuate his troubled appearance.

"Well, Doctor?" said Lucky.

Dr. Gardoma said, "I've got him under sedation. He'll be all right when he wakes. I don't know if he'll remember clearly what happened."

"Has he had attacks like this before?"

"Not since he came to Mercury, Mr. Starr. I don't know what happened before then, but these last few months he's been under a great strain."

"Why?"

"He feels responsible for the accidents that have been interfering with the progress of Project Light."

"Is he responsible?"

"No, of course not. But you can see how he feels. He's sure everyone blames him. Project Light is vitally important. A great deal of money and effort has been put into it. Mindes is in charge of ten construction men, all five to ten years older than he is, and of an enormous amount of equipment."

"How does it happen he's so young?"

The doctor smiled grimly, but despite his grimness his white, even teeth made him look pleasant, even charming. He said, "Sub-etheric optics, Mr. Starr, is a completely new branch of science. Only young men, fresh out of school, know enough about it."

"You sound as though you know a bit about it yourself."

"Only what Mindes told me. We arrived in Mercury on the same ship, you know, and he fascinated me, quite won me over with what his project hopes to accomplish. Do you know about it?"

"Not a thing."

"Well, it involves hyperspace, that portion of space that lies outside the ordinary boundary of the space we know. The laws of nature that apply to ordinary space don't apply to hyperspace. For instance, in ordinary space it is impossible to move faster than the speed of light, so that it would take at least four years to reach the nearest star. In going through hyperspace any speed is possible… " The physician broke off with a sudden, apologetic smile. "You know all this, I'm sure."

"I suppose most people know that the discovery of hyperspatial flight made travel to the stars possible," said Lucky, "but what about Project Light?"

"Well," said Dr. Gardoma, "in ordinary space, light travels in straight lines in a vacuum. It can only be bent by large gravitational forces. In hyperspace, on the other hand, it can be bent as easily as if it were a cotton thread. It can be focused, dispersed, bent back upon itself. That's what the theory of hyperoptics says."

"And Scott Mindes, I suppose, is here to test that theory."

"That's right."

"Why here?" asked Lucky. "I mean, why on Mercury?"

"Because there's no other planetary surface in the Solar System where there is such a concentration of light over so large an area. The effects Mindes is looking for can be detected most easily here. It would be a hundred tunes as expensive to set up the project on Earth, and results would be a hundred times as uncertain. So Mindes tells me."

"Only now we're having these accidents."

Dr. Gardoma snorted. "They're no accidents. And, Mr. Starr, they have to be stopped. Do you know what the success of Project Light would mean?" He drove on, caught up in the vision. "Earth would no longer be the slave of the Sun. Space stations circling Earth could intercept sunlight, push it through hyperspace, and spread it evenly over the Earth. The desert heat and the polar cold would vanish. The seasons would be rearranged to our liking. We could control the weather by controlling the distribution of sunlight. We could have eternal sunlight where we wanted it; night of any length where we wanted it. Earth would be an ak-conditioned paradise."

"It would take time, I imagine."

"A great deal of it, but this is the beginning… Look, I may be out of order here, but aren't you the David Starr who cleared up the matter of the food poisonings on Mars?"

There was an edge to Lucky's voice as he answered, and his brows contracted slightly. "What makes you think so?"

Dr. Gardoma said, "I am a physician, after all. The poisonings seemed at first to be a disease epidemic, and I was much interested in it at the tune. There were rumors about a young Councilman's having played the chief role in straightening the mystery, and names were mentioned."

Lucky said, "Suppose we let it go at that." He was displeased, as always, at any intimation that he was becoming well known. First Mindes, now Gardoma.

Dr. Gardoma said, "But if you are that Starr, you're here, I hope, to stop these so-called accidents."