"Very good," Vosnesensky said. "You did well."

"Yes," answered Reed, "but I’m not so certain that I did right."

"We do not need another doctor here. It will only cause problems. You heard what Li said: already he is thinking of cutting the mission short."

"But, Mikhail Andreivitch, if we are becoming sick…"

"You are the team physician." Vosnesensky pointed a stubby finger at the Englishman. "You find out what is wrong and fix it. One doctor here is enough."

He turned and slid the accordion-fold door open, ending the discussion.

Left alone in his infirmary, Reed drummed his fingers on his desktop. Something was definitely amiss, he knew. Despite the physical exams, there is something incubating here. Vosnesensky would never have reacted like that a week ago. The man was so safety conscious it was almost ludicrous. Now he refuses to consider bringing Yang down here to assist me.

Are we all infected with something? Are we all going mad?

Vosnesensky walked scowling past the galley, straight to his own privacy cubicle. Only then did he let himself sigh wearily and sit on his cot. The air mattress sighed back at him. His legs ached. He felt edgy, almost angry.

Doctors, he grumbled to himself. The more they poke you the more they find that is wrong. We have caught a bug, some form of flu, and for that Li thinks of abandoning the mission altogether. Madness! Absolute madness.

"Are you sick?" Jamie asked.

Ilona looked up at him with bleary eyes. "I don’t know what it is. My arms and legs ache terribly. I don’t seem to have any strength…"

"What did Tony say?"

A guilty look flushed her face. "I didn’t call him. I didn’t want to take the chance that he might order us to return to the dome because of me."

They were in the lab module of the rover, Ilona sitting by the small diamond-tipped saw that they used to slice rocks into thin sections for examination. Jamie was standing next to her in the narrow aisle between the racks of equipment and the workstation counter tops. Joanna sat a few feet away, by the microscope, watching them intently.

"Maybe you should rest," Jamie said.

Ilona shook her head stubbornly. "No. It doesn’t help. And there’s work to do."

Jamie’s own head was throbbing. He felt that Ilona should lie down, that he should call Tony Reed and report that she was sick. But he knew she would argue against it, and he hadn’t the strength to start a fight.

"I’ll be all right in the morning, I’m sure," Ilona said with a forced smile. "I need a good night’s sleep, that’s all."

"We all do," Joanna said. "I haven’t felt this poorly since we all had those colds when we first came aboard the Mars spacecraft."

"You too?" Jamie asked.

"Perhaps there is something wrong with the air filters in here?" Joanna made the suggestion sound like a question. "Perhaps they are not taking enough carbon dioxide out of the air?"

Jamie’s nod made his head hurt even worse. "I’ll check it out." He started for the hatch, then turned back to Ilona. "Take it easy. Don’t push yourself."

"Well, something’s wrong, that’s for sure," Connors said when Jamie got back to the cockpit. "I feel like somebody’s been kickin’ the shit outta me for the past six hours."

"I’d better call Tony," Jamie said. "This is getting serious."

But as Jamie reached for the radio switch on the control panel Connors grabbed his wrist. "Wait till tomorrow morning," the astronaut said.

Jamie gave him a questioning look.

"Never call the medics until you absolutely have to," Connors explained. "All those pill pushers know how to do is tell you to come back home so they can stick needles into you."

"But something’s wrong, you said so yourself."

"You and I will check out the CO₂ system. That might be it. Then we’ll have a good hot dinner and get a good night’s sleep. If we still feel shitty tomorrow morning, then we can call for an ambulance."

Jamie reluctantly agreed.

Seiji Toshima felt that of all the men and women on this exploration team, he was the only one who truly dealt with the entire planet Mars.

Waterman and the others in the rover may be excited about their traverse to the canyon. Patel and Naguib were enraptured by their study of the giant volcanoes. The astronauts and cosmonauts maintained the dome’s equipment while the English physician looked after their health and little Monique tended her garden and studied rocks.

I alone consider this world in its entirety.

He slowly swiveled his creaking plastic chair and surveyed his row of display screens. The entire planet was on view. Three screens showed the whole planet, pole to pole, as seen by the three observation satellites in synchronous orbit. The others showed data recorded by the satellites and roving balloons and the remote beacons that had been placed across the desolate sandy tracts of the red planet: air density, temperature, wind speed and direction, humidity, even the chemical composition of the air.

It was foolish of me, Toshima thought, not to realize that there would be enough humidity in Tithonium Chasma to form mists even in midsummer. He regarded this lapse as a failure of his own. It was known that the canyon floor is two to three kilometers below the surface of the surrounding plains. It was known from the probes that the air density down there was somewhat higher than elsewhere. Of course the air would be somewhat warmer and capable of holding more moisture. I should have foreseen that. I should have predicted it.

He did not dwell on the shortcomings of the past, however. On the largest of all his display screens, the one directly in front of the chair on which he sat, was his masterwork: a fully detailed weather map for the entire planet. Synthesizing all the data coming in to him, Toshima had drawn in the highs and lows, the cyclonic disturbances and wind-flow patterns, for all of Mars. At the touch of a keyboard button he could display the weather as it existed yesterday, or two weeks ago, or as he predicted it would exist tomorrow — or two weeks hence.

The longer-range forecasts were not as firm as the twenty-four-hour prediction, naturally. Even on a world as meteorologically dull as Mars, with no oceans and little humidity to complicate weather patterns, it was difficult to make forecasts more than forty-eight hours ahead. But he was learning, extending the predictive power of his vision further and further.

He rubbed his throbbing temples as he peered closely at his weather map. The dust storms swirling in the northern latitudes fascinated him. Driven by the energy released into the atmosphere by the melting polar cap, they appeared and vanished like ghosts. Unpredictable, so far. Toshima knew that in the spring season such storms could merge together, coalesce into a single gigantic storm that could blot out the whole planet for weeks on end.

He had no fear that these little storms would do that. What worried him was the cold front advancing southward across the broad sweep of Chryse Planitia.

As Martian weather systems went, that cold front contained considerable energy. Noontime high temperatures south of the front were still up into the midtwenties, Celsius. On the other side of the front they were below freezing, even at high noon. The front would pass the eastern end of the Grand Canyon complex during the night. Waterman and the others were more than a thousand kilometers west of there, but still Toshima worried about them.

He did not understand why he was worried. The rover was in no danger from the weather. The four men and women were prepared to face overnight lows of a hundred and fifty below zero. Why was a drop of thirty degrees worrisome?

Toshima felt an inner trembling take hold of him, almost like a sexual urge. There was something in the data before his eyes, something important that he did not recognize. He knew it. He could feel it within him. His subconscious mind was trying to tell him something, awaken him to a revelation, an important discovery. He bit his lips and squeezed his eyes shut, concentrating furiously. In vain.