Leyel Torres, commander of the scientific observation base near the equator on Iscaris III, closed the final page of the report that he had been reading and stretched back in his chair with a grateful sigh. He sat for a while, enjoying the feeling of relaxation as the seat adjusted itself to accommodate his new posture, and then rose to pour himself a drink from one of the flasks on a tray on the small table behind his desk. The drink was cool and refreshing, and quickly dispelled the fatigue that had begun to build up inside him after more than two hours of unbroken concentration. Not much longer now, he thought. Two months more and they should be saying good-bye to this barren ball of parched rock forever and returning to the clean, fresh, infinite star-speckled blackness that lay between here and home.

He cast his eye around the inside of the study of his private quarters in the conglomeration of domes, observatory buildings and communications antennas that had been home for the last two years. He was tired of the same, endless month-in, month-out routine. The project was exciting and stimulating it was true, but enough was enough; going home, as far as he was concerned, couldn't come a day too soon.

He walked slowly over to the side of the room and stared for a second or two at the blank wall in front of him. Without turning his head he said aloud: "View panel. See-through mode."

The wall immediately became one-way transparent, presenting him with a clear view out over the surface of Iscaris III. From the edge of the jumble of constructions and machinery that made up the base, the dry, uniform reddish-brown crags and boulders stretched all the way to the distinctly curved skyline where they abruptly came to an end beneath a curtain of black velvet embroidered with stars. High above, the fiery orb of Iscaris blazed mercilessly, its reflected rays filling the room with a warm glow of orange and red. As he looked out across the wilderness, a sudden longing welled up inside him for the simple pleasure of walking under a blue sky and breathing in the forgotten exhilaration of a wind blowing free. Yes, indeed--departure couldn't come a day too soon.

A voice that seemed to issue from nowhere in particular in the room interrupted his musings.

"Marvyl Chariso is requesting to be put through, Commander. He says it's extremely urgent."

"Accept," Torres replied. He turned about to face the large view screen that occupied much of the opposite wall. The screen came alive at once to reveal the features of Chariso, a senior physicist, speaking from an instrumentation laboratory in the observatory. His face registered alarm.

"Leyel," Chariso began without preamble. "Can you get down here right away. We've got trouble--real trouble." His tone of voice said the rest. Anything that could arouse Chariso to such a state had to be bad.

"I'm on my way," he said, already moving toward the door.

Five minutes later Torres arrived in the lab and was greeted by the physicist, who by this time was looking more worried than ever. Chariso led him to a monitor before a bank of electronic equipment where Galdern Brenzor, another of the scientists, was staring grim-faced at the curves and data analyses on the computer output screens. Brenzor looked up as they approached and nodded gravely.

"Strong emission lines in the photosphere," he said. "Absorption lines are shifting rapidly toward the violet. There's no doubt about it; a major instability is breaking out in the core and it's running away."

Torres looked over at Chariso.

"Iscaris is going nova," Chariso explained. "Something's gone wrong with the project and the whole star's started to blow up. The photosphere is exploding out into space and preliminary calculations indicate we'll be engulfed here in less than twenty hours. We have to evacuate."

Torres stared at him in stunned disbelief. "That's impossible."

The scientist spread his arms wide. "Maybe so, but it's fact. Later we can take as long as you like to figure out where we went wrong, but right now we've got to get out of here. . . fast! "

Torres stared at the two grim faces while his mind instinctively tried to reject what it was being told. He gazed past them at another large wall screen that was presenting a view being transmitted from ten million miles away in space. He was looking at one of the three enormous G-beam projectors, cylinders two miles long and a third of a mile across, that had been built in stellar orbit thirty million miles from Iscaris with their axes precisely aligned on the center of the star. Behind the silhouette of the projector Iscaris's blazing globe was still normal in appearance, but even as he looked he imagined that he could see its disk swelling almost imperceptibly but menacingly outward.

For a moment his mind was swamped by emotions--the enormity of the task that suddenly confronted them, the hopelessness of having to think rationally under impossible time pressures, the futility of two years of wasted efforts. And then, as quickly as it had come, the feeling evaporated and the commander in him reasserted itself.

"ZORAC," he called in a slightly raised voice.

"Commander?" The same voice that had spoken in his study answered.

"Contact Garuth on the Shapieron at once. Inform him that a matter of the gravest urgency has arisen and that it is imperative for all commanding officers of the expedition to confer immediately. I request that he put out an emergency call to summon them to link in fifteen minutes from now. Also, sound a general alert throughout the base and have all personnel stand by to await further instructions. I'll link in to the conference from the multiconsole in Room 14 of the Main Observatory Dome. That's all."

Just over a quarter of an hour later Torres and the two scientists were facing an array of wall screens that showed the other participants in the conference. Garuth, commander-in-chief of the expedition, sat flanked by two aides in the heart of the mother-ship Shapieron two thousand miles above Iscaris III. He listened without interruption to the account of the situation. The chief scientist, speaking from elsewhere in the ship, confirmed that in the past few minutes sensors aboard the Shapieron had yielded data similar to that reported by instruments from the surface of Iscaris III, and that the computers had produced the same interpretation. The G-beam projectors had caused some unforeseen and catastrophic change in the internal equilibrium of Iscaris, and the star was in the process of turning into a nova. There was no time to think of anything but escape.

"We have to get everybody off the surface," Garuth said. "Leyel, the first thing I need is a statement of what ships you've got down there at the moment, and how many personnel they can bring up. We'll send down extra shuttles to ferry out the rest as soon as we know what your shortage in carrying capacity is. Monchar . . ." He addressed his deputy on another of the screens. "Do we have any ships more than fifteen hours out from us at maximum speed?"

"No, sir. The farthest away is out near Projector Two. It could make it back in just over ten."

"Good. Recall them all immediately, emergency priority. If the figures we've just heard are right, the only way we'll stand a chance of getting clear is on the Shapieron's main drives. Prepare a schedule of expected arrival times and make sure that preparations for reception have been made."

"Yes, sir."

"Leyel. . ." Garuth switched his gaze back to look straight out of the screen in Room 14 of the Observatory Dome. "Bring all your available ships up to flight-readiness and begin planning your evacuation at once. Report back on status one hour from now. One bag of personal belongings only per person."