Two dragonflies charged the line of defenders, one behind the other. The first one went down, but the second reached the perimeter. Bram saw a man go down, then there was a flurry of activity as a dozen humans swung at the insect with bats and pikes until it stopped moving.
By now the contracting circumference of men and women had closed up the gaps in the line, and more people were arriving every moment. A hard rain of missiles filled the circle. Bram heard metal ring off the hull of the tug, and something sharp and fast made a small star in the plastic of the viewport.
“What a pitch,” Jao said. “There must be a lot of team-ball players out there.”
“The gravity keeps changing,” Lydis said. “It must be hard to judge.”
“The human brain’s a marvelous computer, Lydis,” Bram said. “You ought to know that.”
The pelting shower of hard objects grew thicker as more people joined in. The nymphs, with their wraparound eyes and their superb ability to detect motion, were good at dodging. But it did them no good when they were bracketed on all sides.
The flat trajectories of the missiles became shallow arcs as gravity increased. But by the same token, the rain of brickbats from above grew harder and harder.
The pitchers were learning to act in unison—picking out one or two targets at a time and concentrating fire on them. By the time the nymphs made the concerted rush that Jao had predicted, there were too few of them left.
These, too, went down under the concentrated stoning. The fact that they were bunched together even helped the humans. Bram tuned into the common wavelength and heard a cheer go up. The defenders swarmed all over the battlefield, making a muddle of light. When Lydis opened the air lock door, quite a crowd was waiting outside.
The elongated figure in the old-fashioned accordion-jointed space suit was Jun Davd. A transparent sack that still held a few unused lumps of metal and ceramic dangled from his hand. He grinned at Bram.
“Did you get them all?” Bram said.
“Yes.”
“There were some that jumped free early. And there are clouds of nymphs out there that the bubble ship shed when we bumped it. They had a net vector toward the tree at the time. I doubt that any of them could survive impact at what the relative velocity was at the time, but…”
“We’ll search the tree. We’ll hunt them down. We won’t rest until we know for sure.”
The curator came swiftly out, clutching the big floppy portfolio he had risked his life for. He refused to let anyone take it from him. Friendly hands led him away toward the nearest entrance to the branch.
“Another iota of the human heritage.” Jun Davd sighed. “We’ve got more of it than we ever bargained for. But we’re leaving so much more behind. After coming all this way, through black holes and exploding galaxies, it doesn’t seem fair to have to run away like thieves.”
Lydis came over and joined them. She had plenty of willing helpers pitching in to secure the tug to the big branch. It would not be sacrificed, after all; somewhere between stars, before Yggdrasil spun again, it could be flown or towed under no-g conditions to an airdock in the trunk.
She pointed at the clot of bubbles that was sinking below Yggdrasil’s horizon. “We ought to be safe from them now,” she said. “There’s no way they can match velocities with us anymore.”
“Let’s be sure,” Jun Davd said.
Five minutes later he had a patch in to Smeth in probe control central, in the trunk. An assistant had hurried over with portable equipment. Bram hadn’t realized the extent of the communication coordination effort that had gone into repelling the dragonfly invaders. There was even a small videoscreen in color—though it was flat, not holo.
They sat outside on the branch to watch; there would not have been time to go inside. Smeth’s voice came in, clear as a bell, from one hundred fifty miles away.
“The bubbles are rising over the horizon now,” Smeth said. “They’re very low—not more than a hundred miles from the treetop. Can you see them?”
In the little portable screen, flecks of spume emerged from behind the curve of the aft horizon. Some remote camera on the other side of Yggdrasil was taking the pictures—probably one of Smeth’s probe monitors. Bram was horrified to see the fiery sprays of exhausts coming from the bubbles, pointing outward; the dragonflies were still trying to land on the tree.
“They don’t realize…” someone murmured. Bram recognized Ame’s voice; she must have gone to probe central to be with Smeth when he returned from the ramjet with his black gang.
“I don’t think they use instruments,” Smeth said in a strained voice. “I think they do everything by vision and instinct.”
“Are you running a parallax on them?” Jun Davd asked.
“Of course,” Smeth snapped. “I’m doing a continuous prediction.”
Bram put the question that was on everyone’s lips. “Are they going to make it?”
“I don’t think so. They think they are. But it’s going to be very close.”
The remote camera tracked the bubbles across Yggdrasil’s sky, gave it up, and another camera—evidently on the trailing branches—picked them up.
“There—they’ve seen their error,” Smeth said.
The bubbles must have rotated all at once; the exhaust plumes now faced Yggdrasil, trying to push the colony vehicles away. But they’d been picking up momentum too long; they continued to fall inward toward a tree that was slipping inexorably past them. They fell past the edge and into the blinding stream of the hadronic photon drive.
They simply vanished. The energy that had instantly vaporized them was such an infinitesimal fraction of the energy flowing around them that they didn’t even make a brief flare.
Bram heard all the sighs of relief through his suit radio. He did a little sighing himself.
A million miles out, they allowed themselves to feel safe. Yggdrasil was hitting almost its full one-gravity acceleration by then—far beyond anything dragonfly technology was able to approach. In a few Tendays, they would be out of the system.
Bram had time enough to clean up, eat something, and grab a few hours’ sleep before he and Mim had to attend the impromptu celebration that was being held in the observation lounge. Marg had decided to cater it at short notice. Word was out that it would feature wines fermented with the help of terrestrial yeasts that had been retrieved from storage on the diskworld.
When he and Mim entered the great curved gallery arm in arm, a couple of thousand people were already milling around. The atmosphere seemed a little subdued for a party. People’s eyes kept stealing to the sweeping expanse of clear plastic that showed the rearward view.
There was no sky behind them—just a solid wall against the firmament. It was blank-faced, featureless, lit only by the receding inferno of Yggdrasil’s artificial sun. Even at a million miles, the top of the wall showed almost no curvature.
Bram got drinks for himself and Mim at one of the bars, then steered her over to the big holo display at the end of the lounge. That had its share of spectators, too. Jun Davd was keeping his telescopes trained on the hairbreadth of rim where what was left of the human race had spent a year digging up its past, and was piping the images to the public displays throughout the tree. Though the images used the holo apparatus, they were flat, showing only what the telescope saw.
Somehow, that made the sight more immediate.
At extreme magnification, the tethered moon was a child’s top poised just above the knife edge of the rim. Its waistline harness and the grid of its engineering structures could be seen fuzzily.