“According to our map we’re still slightly north of Denver,” said Kira. “We’ll go south.” They turned their horses around, Kira whispering encouragements to Bobo and patting him softly on the neck. The riverbank itself was impassable, not just along the shoreline but several yards back from it, nearly a full quarter mile in some places. The ground was either too steep or too swampy or too dense with trees, and more often than not all three. They followed a narrow highway as far as they could, though more than once they found that it had wandered too close to the river and sloughed off, washing away into the relentless flood of water. When that road turned away they moved to a different one, though the story was similar there and occasionally worse. The first bridge they found looked across to the biggest city since Chicago, but this bridge was destroyed, just like the last one. The second day they found themselves trapped where the road had been completely washed away, surrounded on one side by the river and the other by a lake, and were forced to backtrack several miles. Here the wetlands stretched well over a mile from bank to bank, probably more than two, though Kira couldn’t help but wonder how much of her estimate was accurate and how much was helpless frustration. It was beautiful, alive with birds and flowers and fireflies turning lazy circles over the marsh, but it was also insurmountable. They found a new road, prayed that it would take them to a bridge, and followed it south.

After two days of searching they came to the village of Gulfport, more under the water than over it. Heavy stone pylons marked where a bridge had once stretched across to the much larger city on the far side, but except for some girders peeking forlornly from the surging river currents, nothing but the pylons remained. Kira swore, and Afa slumped painfully in his saddle. Even Oddjob, usually eager to wander during their pauses in search of green shoots to munch on, seemed too depressed to move.

“It’s got to be the river that took out the bridge,” said Samm. “These cities were too small to be a factor in the war, and none of them are military targets. I think the river’s just too . . . big for its own good.”

“Two big for our own good, too,” said Heron.

“Somebody had to cross it first, right?” asked Kira. She nudged Bobo’s flanks and walked him farther toward the water’s edge, peering around the bend in the trees as far south as she could see. “I mean, somebody had to build the bridges, and somebody had to cross before that.”