It was his job to reach out to Aaron. Perhaps it wasn't too late to be friends. He had to try.
Just after local noon Justin and Jessica flew barely thirty meters above the river and followed it south toward the fork. It was an old river with many twists and turns, but it ran fairly straight here as it fell four hundred meters in less than twenty klicks. Tau Ceti burned brightly through thin high clouds, and Justin watched Skeeter l's shadow as it was overtaken by Little Chaka's craft. He resisted the urge to turn their trip into a race: Big Chaka was Skeeter IV' s passenger, and Big Chaka hated speed.
Their radio crackled. "How close have you been?" Big Chaka asked.
"We've scouted by air many times," Jessica answered. "Haven't had time to organize a trip on foot. That's grendel country, and we try to stay out, because the only way we know to deal with a grendel is to flush it out and shoot it."
"And that tends to disrupt the ecology," Justin said. "Aaron doesn't like that."
"Nor should he," Chaka said.
"Yeah. Anyway, this is a genuine Avalon Surprise. We seem to find a new one every week."
They were approaching the fork where two rivers combined to become the big river that ran south past Deadwood and on to the sea. They turned to follow the northwest branch, and just beyond the fork Little Chaka slowed and hovered his skeeter. They were above a wide rough oval of blue water. At the far downstream end the hills on either side of the stream came together to form a narrows. A line of boulders stood in the water there, and behind the boulders a matted webbing of tree trunks and branches formed a dam. Broad, powerful dark shapes swam in the lake.
Justin held his breath. This was something that they hadn't even videoed for Cassandra. Little Chaka wanted it as a surprise for his father. There was a long pause. Skeeter IV hovered only twenty meters or so above the water. The water surface rippled in waves. A broad, powerful shape glared up at them. Its oddly flattened body reminded Justin of an aquatic ankylosaurus. Broad, powerful tail, triangular head. He wondered if it had feet, or flippers. One thing was certain: despite the surface differences, they were looking at a variety of grendel.
"Like a beaver dam," Big Chaka finally said, wonderingly. "It's beautiful."
Jessica and Justin exchanged smiles. "Have you ever actually seen one.
Dr. Mubutu?" she asked.
"You bet. In Kalamazoo, Michigan, where I grew up."
"And there—" Little Chaka said. "Do you see?"
"I sure do, son." Big Chaka's voice held deep contentment, as if he were listening to a new music composition, or enjoying a good meal. "Two grendels are pushing that log into place, and another is watching us watch them. Take us closer to that spillway, please. The one on our right."
"Sure—"
"As I thought," Big Chaka said. "Note the branches placed at the spillway: They're straining the water there, but—now look at the other spillway area. A different structure."
Justin steered the skeeter to the downstream end of the lake and hovered above the dam. "I never noticed that," he said. "But look, they strain the water over there, here there's that series of pools. Reminds me of—Cassandra, what does that remind me of?"
"Searching—"
"Salmon ladders," Big Chaka said.
"Fish ladders," Cassandra said at almost the same time. "Structures to allow fish to swim upstream at dam sites. Used extensively on the North American continent on Earth."
"Cassandra. Enlarge those animals," Little Chaka said.
Jessica linked with Chaka, so that she could get the same visuals. A holographic window opened in the middle of their windscreen.
"Beautiful," Big Chaka repeated. "Just what I thought."
There was no doubt about it. There were at least six shapes in the water. A scale running at the lower edge of the screen said that they were about two meters in length. Two of them carried chunks of tree limb. Two were wedging mud into the cracks of their dam. A grendel's work is never done.
"Social cooperation," Big Chaka breathed. "We wouldn't have believed it back in the old days, but I knew that something like this might exist. Now take us upriver, and set us down about a klick or so above the dam."
The two skeeters wheeled northward. "Cassandra," Justin said. "Safety scan, please."
"I see nothing in your area. The lake grendels are concerned with their dam."
"Is this the only dam?" Big Chaka asked.
"Negative," Cassandra answered. "Prior to the recent flooding there were seven between here and the sea, and I can identify four more upstream. The nearest downstream from here is fifty-seven kilometers to the southwest."
"Thank you."
"Should we land?" Justin asked.
"I see no obvious danger," the computer answered. "I cannot answer the question as asked."
"Cancel," Justin said. "All right, it looks safe. Let's do it."
They landed on a mound of rock fifty meters from the river. Jessica was out first, grendel gun at the ready. Big Chaka had already shouldered his backpack. He darted toward the river. "I need water samples."
"Are you sure about that?" his son asked, anxiously.
"Absolutely. You don't think that these creatures would go through all the trouble to build a dam like this if they could hunt, do you?"
"I don't know. But if they can cooperate with each other, why can't they cooperate with hunters?" Justin demanded. "Oh, well." Justin swung down out of the pilot's seat and checked his rifle.
"Cassandra. What observation capability do you have?"
"Satellite Four will remain in observing range for twelve minutes, resolution one meter," the computer answered. "There are grendels in the water six hundred meters downstream. I detect no large land animals near you."
"Keep looking." The river looked peaceful. Maybe fifteen kilometers northwest, snowcapped mountain peaks stood out with startling clarity. There was another range visible to the northeast, and behind that range the Veldt stretched north and east for a thousand kilometers.
"Come on," Big Chaka called out. Little Chaka carried a handheld scanner, and a rifle slung over his right shoulder.
Justin caught up with Little Chaka. "He lives for this, doesn't he?" Justin scanned the river. His head swept slowly from left to right. He knew, without looking, that Jessica was doing the same.
The riverbed clay was yellowish, sun-blasted and cracked in rivulets. The warped and twisted trees along the banks suggested alternate periods of flood and drought.
"What are you looking for?" Little Chaka asked.
"Samples. The usual," his adopted father said, but there was something about his voice that said: I'm not ready to talk about it yet.
"Does this have anything to do with the grendel autopsy?" Jessica asked. "Or the deaths?"
"Everything on Avalon has to do with grendels." Big Chaka smiled faintly. "Maybe one day that won't be true. But for now... "
He knelt down and took a flask from his pocket. He scooped a small sample of mud into it. "Is this where Tonya was swimming when she picked up the fluke?"
"No, of course not," Little Chaka said. "We don't swim here. There are grendels out there!"
"Ah. Well, it will have to do," Big Chaka said.
Little Chaka looked at his scanner. "I really don't want to stay here any longer than we have to."
Big Chaka nodded regretfully. He looked down to the south. Six hundred meters away, grendels were operating within a social contract. He would have to see that phenomenon, and study it at length.