“We were naïve,” Thomas said suddenly as he and Ben approached the ruined Post Office Building. “We thought there would be a few buildings standing with open doors. All we had to do was walk in, pull out a drawer or two, and get everything we wanted. Be heroes when we got home. Stupid, wasn’t it?”

“We’ve already found out a lot,” Ben said quietly.

“What we’ve learned is that this isn’t the way,” Thomas said sharply. “We aren’t going to accomplish anything.”

They circled the building. The front of it was blocked; around the side, one wall was down almost completely; the insides were charred and gutted.

The fourth building they tried to enter had burned also, but only parts of it had been destroyed. Here they found offices, desks, files. “Small business records!” Thomas said suddenly, whirling away from the files to look at Ben excitedly.

Ben shook his head. “So?”

“We came through a room with telephone directories! Where was it?” Again Ben looked mystified, and Thomas laughed. “Telephone directories! They’ll list warehouses! Factories! Storage depots!”

They found the room where several directories lay in a pile on the floor, and Thomas began to examine one intently. Ben picked up another of the books and started to open it.

“Careful!” Thomas said sharply. “That paper’s brittle. Let’s get out of here.”

“Will that help?” Ben asked, pointing to the directory Thomas carried.

“Yes, but we need the central office of the telephone company. Maybe Molly can find it.”

That afternoon, the next day, and the next the search for useful information continued. Molly updated her Washington map, locating the buildings that contained anything of use, noting the dangerous buildings, the flooded sections — many of the basements were filled with evil-smelling water. She drew many of the skeletons they kept stumbling over. She sketched them as dispassionately as she did the buildings and streets.

On the fourth day they found the central telephone offices, and Thomas stationed himself in one of the rooms and began to go through the directories of the eastern cities, carefully lifting out pages they could use. Ben stopped worrying about him.

On the fifth, and sixth days it rained, a steady gray rain that flooded the low-lying areas and brought water above the basement level in some of the buildings. If the rain kept up very long, the whole city would flood, as it evidently had done over and over in the past. Then the skies cleared and the wind shifted and drove in from the north, and they shivered and continued the search.

As she drew, Molly thought: millions of people, hundreds of millions of people, all gone. She drew the ruined Washington Monument, the broken statue of Lincoln and the words of the inscription that remained on the pedestal: One nation indi . . . She drew the skeletal frame of the Supreme Court Building . . .

They didn’t move camp to the city, but slept aboard the boat every night. They were amassing too much material to take back with them; every evening when they left the city they took back loads of records, books, maps, charts, and after the evening meal each of them went over his own stack of material and tried to sort it. They made extensive notes about the condition of the buildings they explored, the contents, the usefulness of the material in them. The next expedition would be able to go straight to work.

There were the skeletons, some of them on top of the rubble, some half buried, others in the buildings. How easily they could ignore them, Ben mused. Another species, extinct now, a pity. Pass on.

On the ninth evening they made the final choices of what to pack in the boat. They found an intact room in a partially destroyed building and stored the surplus material there for the next group.

On the tenth day they started for home, this time rowing against the current, with a fresh breeze blowing from the northeast, puffing the large single sail they had not been able to use until now. Lewis attached the tiller, and the wind drove them up the river.

Fly, fly! Molly silently urged the boat. She stood in the prow and sang out the hazards, some of them almost before they came into sight. There was a tree stump there, she remembered; and again, a train engine; a sand bar . . . In the afternoon the wind shifted and blew in from due north, and they had to take down the sail or risk being driven onto shore. Gradually the excitement they had all felt earlier gave way to dogged determination, and finally to mindless patience, and when they stopped for the night they all knew they had traveled little more than half the distance they had traveled on this leg of their journey toward the city.

That night Molly dreamed of dancing figures. Joyously she ran toward them, arms outstretched, her feet not touching the ground at all as she raced to join them. Then the air thickened and shimmered and the figures were distorted, and when one of them looked at her, the outline of her face was all wrong, her features wrong, one eye too high, her mouth bent out of shape. Molly stopped, staring at the grotesque face. She was drawn toward it relentlessly through the thick air that changed everything. She struggled and tried to hang back, but her feet moved, her body followed, and she could feel the resisting air close about her suffocatingly. The caricature of her own face grimaced, and the figure raised snake-like arms toward her. Molly came wide awake suddenly, and for several moments didn’t know where she was. Someone was shouting.

It was Thomas, she realized, and Ben and Lewis were struggling with him, getting him out of his bunk, toward the bow of the boat, the canopied section. Harvey moved to the rear and gradually quiet returned, but it was a long time before Molly could go back to sleep.

By the third day the return trip had turned into a nightmare. The wind became gusty, more dangerous than helpful, and they no longer tried to use the sail. The current was swifter, the water muddy. It must have rained much more inland than it had in Washington. Also, the air had a chill that persisted until midday, when the sun became too hot for the warm clothing they had put on earlier. By sundown it was too cool for the lighter garments they had changed into at the lunch break. They were always too hot or too cold.

Ben and Lewis withdrew from the others and watched the sunset from a rise over the river. “They’re hungry, that’s part of the trouble,” Ben said. Lewis nodded. “Also, Molly has started her menstrual period and she won’t let anyone near her. She nearly bit poor Harvey’s head off last night.”

“I’m not worried about Harvey,” Lewis said.

“I know. I don’t know if Thomas is going to make it or not. I tranquilized him at dinner. I don’t know from one day to the next what to expect from him.”

“We can’t carry a dead weight home with us,” Lewis said grimly. “Even with strict rationing, food’s going to be a problem. If he’s tranquilized, he’ll still need to eat, someone else will have to row for him .

“We’ll take him back with us,” Ben said, and suddenly he was in command. “We’ll need to study him, even if he goes home in restraints.”

For a moment they were both silent. “It’s the separation, isn’t it?” Lewis looked south, toward home. “No one predicted anything like this. We’re not like them! We have to scrap the past, the history books, everything. No one predicted this,” he said again quietly. “If we get back, we have to make them understand what happens to us away from our own kind.”

“We’ll get back,” Ben said. “And that’s why I need Thomas. Who could have foreseen this? Now that we’re aware of how different we are from them, we’ll be looking harder. I wonder where else differences will show up when we’re not expecting them to.”

Lewis stood up. “Coming back?”