There was a growing knot of unreasoned panic rising within him, urging him to run, scream, escape. He fought it down and turned deliberately and started back toward the room where Arinix was waiting. He would spend the'rest of the hour waiting for that door to open, hoping he would have the control to prevent himself from beating upon it. Something had happened, to him or the world, he did not know which, but he did know that the only hope of salvation from the incredible events of the morning lay beyond that door. Screaming unreason wanted him to run; he walked slowly, noticing for the first time that the street he was walking down ended in the water. The buildings on each side sank into it as well, and there, at the" foot of the street, was the roof of a drowned wharf. All this seemed no more incredible than anything that had happened before, and he tried to ignore it. He fought so hard to close his mind and his thoughts that he did not hear the rumble of the truck motor or the squeal of brakes behind him.
"That man! What are you doing here?"
Mark spun about. A dusty, open-bodied truck had stopped at the curb, and a thin blond soldier was swinging down from the cab. He wore a khaki uniform without identifying marks and kept his hand near the large pistol in a polished leather holster that swung from his belt. The driver was watching him, as were three more uniformed men in the back of the truck, who were pointing heavy rifles in his direction. The driver and the soldiers were all black. The blond officer had drawn his pistol and was pointing it at Mark as well.
"Are you with the westenders? You know what happens to them, don't you?"
Sudden loud firing boomed in the street, and thinking he was being shot at, Mark dropped back against the wall. But no shots were aimed, in his direction. Even as they were turning, the soldiers in the truck dropped, felled by the bullets. Then the truck itself leaped and burst into flames as a grenade exploded. The officer had wheeled about and dropped to one knee and was firing his pistol at Arinix, who was sheltered in a doorway across the street, changing clips on the submachine gun he carried.
Running footsteps sounded, and the officer wheeled to face Arinix's companion, who was running rapidly toward him, empty-handed and cold-faced.
"Watch out!" Mark called as the officer fired.
The bullet caught the running man in the chest, spinning him about. He tottered but did not fall, then came on again. The second shot was to his head, but before the officer could fire again, Mark had jumped forward and chopped him across the wrist with the edge of his hand, so that the gun jumped from his fingers.
"Varken hand!" the man cried, and swung his good fist toward Mark.
Before it could connect, the runner was upon him, hurling him to the ground, kicking him in the head, again and again, with a heavy boot. Mark pulled at the attacker's arm, so that he lost balance and had to stagger back, turning about. The bullet had caught him full in the forehead, leaving a neat, dark hole. There was no blood. He looked stolidly at Mark, his features expressionless, his skin smooth and shiny.
"We must return quickly," Arinix said as he came up. He lowered the muzzle of the machine gun and would have shot the unconscious officer if Mark hadn't pushed the barrel aside.
"You can't kill him, not like that."
"I can. He is dead already."
"Explain that." He held firmly to the barrel. 'That and a lot more."
They struggled in silence for a second, until they were aware of an engine in the distance getting louder and closer. Arinix turned away from the man on the sidewalk and started back down the street. "He called for help on the radio. We must be gone before they arrive."
Gratefully Mark hurried after the other two, happy to run now, run to the door to escape this madness.
3
"A drink of water," Arinix said. Mark dropped onto the metal bench in the brown room and nodded, too exhausted to talk. Arinix had a tray with glasses of water, and he passed one to Mark, who drained it and took a second one. The air was cool here, feeling frigid after the street outside, and with the water, he was soon feeling better. More relaxed, at ease, almost ready to fall asleep. As his chin touched his chest, he jerked awake and jumped to his feet.
"You drugged the water," he said.
"Not a strong drug. Just something to relax you, to remove the tension. You will be better in a moment. You have been through an ordeal."
"I have… and you are going to explain it!"
"In a moment."
"No, now!"
Mark wanted to jump to his feet, to take this strange man by the -throat, to shake the truth from him. But he did nothing. The desire was there, but only in an abstract way. It did not seem important enough to pursue such an energetic chain of events. For the first time he noticed that Arinix had lost his hairpiece during the recent engagement. He was as hairless as an egg, and the same scars that crisscrossed his face also extended over his bare skull. Even this did not seem important enough to comment upon. Awareness struck through,
"Your drug seems to be working."
"The effect is almost instantaneous."
"Where are we?"
"In New York City."
"Yes, I know, but so changed. The water in the streets, those soldiers, and the heat. It can't be January-have we traveled in time?"
"No, it is still January, the same day, month, year it has always been. That cannot be changed, that is immutable."
"But something isn't; something has changed. What is it?"
"You have a very quick mind, you make correct conclusions. You must therefore free this quick mind of all theories of the nature of reality and of existence. There is no heaven, there is no hell, the past is gone forever, the unstoppable future sweeps toward us endlessly. We are fixed forever in the now, the inescapable present of our world line-"
"What is a world line?"
"See… the drug relaxes, but your brain is still lawyer-sharp. You live in a particular present because of what happened in the past. Columbus discovered America, the armies of the North won the Civil War, Einstein stated that E = MC2"
He stopped abruptly, and Mark waited for him to go on, but he did not. Why? Because he was waiting for Mark to finish for him. Mark nodded.
"What you are waiting for is for me to ask if there is a world line where Columbus died in infancy, where the South won, and so forth. Is that what you mean?"
"I do. Now, carry the analogy forward."
"If two or three world lines exist, why, more, any number, an infinity of world lines can exist. Infinitely different, eternally separate." Then he was on his feet, shaking despite the drug. "But they are not separate. We are in a different one right now. There is a different world line beyond that door, down those steps-because the ground here is at a different height. Is that true?"
"Yes."
"But why, how… I mean, what is going on out there, what terrible thing is happening?"
"The sun is in the early stages of a change. It is getting warmer, giving out more radiation, and the polar ice caps are beginning to melt. The sea level has risen, drowning the lowest parts of the city This is midwinter, and you saw how warm it is out there. You can imagine what the tropics are like. There has been a breakdown in government as people fled the drowning shorelines. Others have taken advantage of it. The Union of South Africa has capitalized on the deteriorating conditions, and using mercenary troops, has invaded the North American continent. They met little resistance."