night's sleep."

They traveled fast, and now and again Mark pointed out where the others had camped, where they had gone astray, where they had realized their error and headed in the right direction again. On the second day his lips tightened and he looked angry, but said nothing until late in the afternoon. "They're too far west, getting farther off all the time," he said. "They might miss Philadelphia altogether if they don't head east again. They must have been trying to bypass the swamps."

Barry was too tired to care, and Anthony merely grunted. At least, Barry thought, stretching out by the fire, they were too tired at night to listen for strange noises, and that was good. He fell asleep even as he was thinking this.

On the fourth day Mark stopped and pointed ahead. At first Barry could see no difference, but then he realized they were looking at the kind of stunted growth Mark had talked about. Anthony unpacked the Geiger counter and it began to register immediately. It became more insistent as they moved ahead, and Mark led them to the left, keeping well back from the radioactive area.

"They went in, didn't they?" Barry said.

Mark nodded. They were keeping their distance from the contaminated ground, and when the counter sounded its warning, they moved south again until it became quieter. That night they decided to keep moving west until they were able to get around the radioactive area, and enter Philadelphia from that direction, if possible.

"We'll run into the snowfields that way," Mark said.

"Not afraid of snow, are you?" Barry said.

"I'm not afraid."

"Right. Then we go west tomorrow, and if we can't turn north by night, we come back and try going east, see if we pick up a trail or anything that way."

They traveled all day through an intermittent rain, and hourly the temperature fell until it was near freezing when they made camp that night.

"How much farther?" Barry asked.

"Tomorrow," Mark said. "You can smell it from here." Barry could smell only the fire, the wet woods, the food cooking. He studied Mark, then shook his head.

"I don't want to go any farther," Anthony said suddenly. He was standing by the fire, too rigid, a listening look on his face.

"It's a river," Mark said. "It must be pretty close. There's ice on all the rivers, and it hits the banks now and then. That's what you hear."

Anthony sat down, but the intent look didn't leave his face. The next morning they headed west again. By noon they were among hills, and now they knew that as soon as they got high enough to see over the trees they would be able to see the snow, if there was any snow to see.