In an artificially constructed chamber somewhere in the solar system, an intelligent being sat before a bank of instruments that was designed to bring to his attention various factors concerning the things that mattered to his species. This being had been on duty for the average length of time such a duty entailed and had been paying little conscious attention to the routine—for there had been nothing to report for some time.

The drop in channeling from Planet III that had occurred some time ago had thus far not caused too much concern. It was assumed by the other intelligent beings involved that the matter was possibly a weather condition, a volcanic discharge or quite simply that the planet was in unfavorable orbit. Not all the stations ever worked simultaneously. There were always some behind the Sun, or blocked in some other manner. But the main channels were at work, and the different lines and shifts continued to build up satisfactorily.

But now something occurred that focused the attention of the watcher more closely on his instruments. A facet of his panel had flashed a color at the lowest end of his visible spectrum. How the being registered that color cannot be said; the inhabitants of Planet III would have termed it red.

With trained reaction, the watcher activated the full signal. Instantly there appeared before his eyes a vision of a scene. There was the interior of the major station on Planet I. It was non-functioning, and there were two strange creatures turning now to look directly at him. They were bipeds with two armlike extensions, lumpy objects, clad in bulky white folds. They wore cumbersome helmets and he could see two eyes shielded beneath thick transparencies over the face.

One of these creatures raised his arm and there was a puff of steam. Then the vision flashed off, but not before the trained watcher had activated the crash mechanism.

If the watcher had been closer in space to the station, the destruction would have come quicker. Unfortunately for him, the speed of light and radio impulses is limited, so that it was several minutes before the destruction impulse reached Planet I.

A short while later, after the guiding beings had digested the news, preparations were made for a vessel to go sunward to investigate—and remove—the interference.

Burl twisted on his heel sharply as he whirled around to look at the flash of red. Boulton drew his hand weapon, aimed and fired.

There was a jet of steam as the compressed air blasted the dart from the gun. The glowing globe was pierced, there was a small explosion, and then the globe and its pedestal vanished.

"What was that?" cried Burl.

Boulton holstered his gun. "A signal of some kind—a warning probably. My guess is that it was an alarm tipping off the remote control masters of this place that it was out of commission. Help me with the photo stuff; I think we'd better get out of here quick!"

Without wasting more time, the two men snapped the scene as fast as the shutters would click. Then they picked up the cameras, grabbed their umbrellas and ran for the break in the wall.

Just as they made their first flying leaps toward the shielded rocket plane, the globes within the Sun-tap station started to go off. One after another, like a chain reaction, they blew up, and within seconds the interior of the walled station was a turmoil of falling metals, beams, wires, and sharp transparent shards.

Haines and Ferrati were ready for take-off and puffs of smoke were coming from the exhaust. Without bothering to take down the plastic Sun-shield, Burl and Boulton tumbled into the cabin. Before the door was even closed, Haines lifted the ship and headed for the dark depths of the canyon.

The inside of the plane was perilously hot. The shield had been a temporary protection, but even the ground radiated heat like an oven. They had to seek the cold of the sunless canyon to allow some of the heat to escape. To have flown directly to the Magellan without cooling the plane would have been disastrous.

The Magellan emerged from the cold side to meet them. From the heights of space, they saw that they would not need to bomb the mountain relayer masts—for the same alarm that had triggered the station had shattered them.

After the Magellan had scuttled back to the cold side, there was a council of war in the control room. Burl and Boulton described very carefully what had happened.

"This must have been their primary station," said Russ thoughtfully. "No matter what they seek to channel from the Sun on other planets, it is from here that the first and strongest diversion of solar energy must have been coming. This station may have been the last constructed—the final link put into place. And for that reason, they installed an alarm."

"Ah," said Lockhart, "even if they did, would it necessarily have destroyed the station? After all, they would normally have figured on repairing whatever went wrong."

"It seems to me," said Burl, "that the red flash itself didn't start the destruction. There was a delay—must have been several minutes—before it started. Could it be, that what was alerted was a watcher?"

"Where?" said Boulton. "There was no place for a watcher to be in that station. We saw no sign of it."

"Maybe deep underground?" suggested the engineer, Caton. "They might have living quarters a few miles underneath."

"Highly unlikely," said Russ Clyde. "It would still be too hot, and, remember, these people plan to incinerate Mercury and the inner planets. They must be from the edge of the system. The delay may be a valuable clue to that. It would take time for a remote control station on another planet to see what was happening and take steps. If you can figure out exactly how many minutes and seconds elapsed between the flashing of the red bulb and the blowup, we could work out the approximate distance."

But, unfortunately, the time could not be judged that accurately. Neither Burl nor Boulton had had time to look at his watch.

They hung over the cold side of Mercury for several hours more while the two astronomers figured their next move. When the orbits had been determined, the Magellan turned its massive wide nose away from the Sun toward a gleaming white disc that dominated the dark skies of outer space. With full power on, they pushed away from the littlest planet and began the long fall toward the Sun's second planet, that which some had considered to be Earth's veiled twin, Venus.

There was a matter of thirty million miles to cross, and the crossing would be made fighting the pull of the Sun all the way.

Caton and his men had spent the wait on Mercury working on the great generators in the powerhouse nose. They recalibrated the output and corrected it from the records kept during the flight inward. Now they were confident of its ability to drive the ship away from the Sun. Coming in, they had not been sure what their A-G drive would do and could do. Going outward they knew just what to expect.

They did not travel blindly outward, for that would have been both a crude waste of power and inaccurate. Instead, the ship drove at a long slant from the Sun, moving in a gently curving orbit that would bring it onto Venus at the same time that Venus itself was moving along in its orbit. This is what they had tried to do before, but without success. Venus travels around the Sun at a speed of about 32 miles per second, and takes about 224.5 days to complete the circuit. From where the Magellan took off, it would approach and overtake Venus at a speed a little greater than the 32 miles per second.

The days passed swiftly enough. They had developed the pictures taken in the Mercury station, and the engineers and astronomers spent long hours debating their features, matching up what they had seen with what was known about the Andes station.

The shining face of Venus grew larger. It was a mysterious planet, the most mysterious in the system, even though it was the closest of the planets to Earth. Venus was a world whose atmosphere—of Earthly depth—was a solid mass of clouds. Never had the clouds lifted to reveal the surface. The clouds reflected the sunlight brilliantly, yet as Burl could now see with the naked eye, parts of it were hazy, as if mighty storms were raising dark particles from below.

"We've had a couple of prober rockets shot into its surface," said Russ, as they watched the oncoming planet. "They didn't prove much—faded out fast, but we think they established its length of day. Nobody knew how many hours it took Venus to rotate on its axis. Some even thought it always presented one face to the Sun as does Mercury. Others thought it had a quick day, shorter than Earth's. Others gave it a day almost a month long.

"Our prober rockets, carrying unmanned instruments, rather definitely indicate that the planet has a day about twenty Earth-days long. Even though it's shielded by the clouds, it must be miserably hot near the surface."

"We'll soon find out." Burl grinned. "After Mercury, it couldn't be so bad. Maybe it rains all the time."

Russ shrugged. "Who knows?" he said.

Venus was a vast sea of swirling white and gray clouds beneath them when the Magellan reached it. They hung above the cloud level, while stretching below them lay the circular bowl of veiled mystery that was the fabled evening star of poem and song.

Oberfield was probing the surface with the radiation counters for the Sun-tap distortion. None had been detected from Earth, but observation of the sunny face of Venus had always been difficult from the third planetary orbit. But quickly the dour astronomer proved the fact. A calculation of the planet's albedo—its rate of reflected sunlight—showed that in one large central section there was a dimming out. Somewhere in that spot, the light was being diverted.

Lockhart brought the Magellan down gradually, closer, closer, and finally sank it into the soupy atmosphere of Venus. Now, from every viewplate, nothing reflected but a glare of white mist. But the ship was not operating blind. Radar pierced the clouds, and from the wide screens the crew could see that they had not yet touched the surface.

"Watch out for mountains," whispered Russ, hanging over Lockhart's shoulder.

Their progress was slow but steady. The cloud bank around them did not clear, but still glowed gray. After a descent of nearly two hours, there was a flicker on the radar. It registered no features, no mountains, nothing but a seemingly flat plain.

Above and around them the white clouds still blanketed everything. But now Burl thought he saw a pale glow. Gradually the white faded away into wisps and shreds, and in a flash the ship broke out of the clouds.

They hung beneath a grayish-white sky. Below them, scarcely a half mile of visibility in misty, thin air, they saw the surface of Venus. They were over water. An ocean stretched below them as far as the eye could see, with neither a rock nor an island. Venus was a water world!