Jill was leaving Rather behind. She glanced back once and moved on, and there was laughter in the sound of her panting.

Jill was his elder by half a year. When he wanted company it was generally Jill he wanted; but they did compete.

There had been a year during which she could beat him at wrestling, when she suddenly grew tall and he’d lagged behind. She’d taught him the riblock the hard way: she’d held his floating ribs shut with her knees so that he couldn’t breathe. He could wrestle her now — he was a boy and a dwarf — but her longer arms and legs gave her an unbeatable advantage at racing. He’d never catch her.

So he moved outward at his own pace, giving due care to his handholds and footholds in the rough bark, following the blond girl in the scarlet tunic. Her long-limbed mother had already reached the CARM ahead of them.

At fourteen-plus. Rather was considered an adult. He was built wide and muscular, with heavy cheek, jaw, and orbital bones. His fingers were short and stubby, and his toes, though strong, were too short to be much use. His hair was black and curly like his mother’s. His beard was sparse, without much curl to it yet. His eyes were green (and green tinged his cheek, with a growth of fluff that would be many days healing). He stood a meter and threequarters tall.

Dwarf. Arms too short, legs too short. He should have gone around the trunk. Jill could have told the Scientist about the burning tree; Debby might already know. He could have been getting a closer look!

The CARM loomed ahead of him. It was as big… no, bigger than the Citizens Tree commons.

Debby shouted into the airlock. Someone emerged:

Jeffer. They talked, heads bobbing. Debby moved to the front of the CARM; Jeffer was about to go back inside—

Rather heard Jill calling. “Scientist! There’s a burning tree coming toward us!” She paused to catch her breath.

“We saw it, me and Rather, we — while we were swimming—”

Jeffer called back. “Debby told me. Did you see anything like winged men?”

“…No.”

“Okay. Help Debby with the moorings, there at the bow.” He noticed Rather struggling in Jill’s wake. “Get Rather to help you.”

Debby and Jill were both fighting knots, and Jill was muttering “Treefodder, treefodder, treefodder,” when Rather caught up. “I bent my finger,” she said.

Debby said, “I hate to cut lines. See what you can do.”

The CARM’s tethers hadn’t been moved in years, and the knots were tight. Rather’s stubby fingers worked them loose. Dwarf. Clumsy but strong. Presently the CARM was held by nothing but its own inertia. Jill did not look pleased. Debby and Rather grinned at each other. It was something, to do a thing an adult warrior could not!

Jeffer called from the airlock, twelve meters beyond the bark. “Come aboard!”

Debby jumped and Jill followed. Rather hesitated until he saw them bump against the airlock door. The jump looked dangerous. Tide was gentle, but one could fall into the sky. Rather had never been inside the CARM, and he wasn’t sure he wanted to be. The starstuff box was like nothing else in or on the tree.

But he had to follow. He caught the edge of the outer door as it passed, pivoted on the strength of his arms, and entered feet first. Can’t jump right, can’t reach far. What if I missed?

It was weird inside the CARM. There were openings in the back wall, and hard round loops sticking out of the dorsal and side walls. Farther toward the front were rows of cradles almost the size of an adult, ten in all, made of nothing like wood or cloth.

Rather made his way forward. The others were in the first row of cradles. “Take a seat and strap yourself in,” Jeffer ordered. “Here, like this.” He fastened two elastic tethers across Jill’s torso. “Lawri showed me how to work these, years ago.”

The cradle had a headrest that fitted nicely behind his ears. Jill’s and Debby’s dug into their shoulders. It’s true, Rather thought suddenly. The CARM was built for dwarves! He liked the thought.

“The winged men weren’t very close,” the Scientist said. “We’ve got time.” His fingers drummed against the flat panel below the window.

There was tide pulling Rather forward, and a whisperroar like a steady wind. The bark receded; the tree backed into the sky. Jill gripped the armrests of her cradle. Her mouth was wide. Debby said, “Clave didn’t say take off, Scientist. He said get ready.”

“No time. They’re headed for the trunk. Also the CARM is mine, Debby. We settled that once.”

“Tell it to Clave.”

“Clave knows.”

The invaders kicked themselves through the air, slowly, in the last stages of exhaustion. Five, it looked like, until Rather realized that the older woman carried a half-grown girl in her arms.

Jeffer nudged the CARM toward them, in along the trunk.

Smoke Ring people came long, longer, or dwarf. These invaders were of the longer persuasion, like jungle giants, born and raised in free-fall. They were quite human: an older man and woman and four girls. The wings were artificial, bound to their shins, made of cloth over splayed ribs. One girl trailed behind, struggling along with only one wing.

They were in sorry shape. Closer now, and Rather could see details. The man’s hair was burned, and the loose sheet that covered him was charred. The wingless girl was coughing; she didn’t even have the strength to cling to the woman who carried her.

Their legs stopped pumping as, one by one, they saw the CARM.

Debby said, “I don’t see anything like bows or harpoons. Can we take them aboard?”

“I thought of that, but look at them. The CARM scares them worse than being lost in the sky. Anyway, the man’s almost there.”

The burned man hadn’t seen them. Kicking steadily, far ahead of the others, he reached the bark and clung.

Without a pause he pounded a stake into the bark, moored a coil of line, and hurled the coil at the older woman. She freed a hand and caught it, pulled herself toward the tree, then snapped the line to send a sine wave rolling toward the trunk. The nearer girl caught the line in her toes as it bowed toward her.

Clave came around the bulge of the bark. He slowed when he saw the strangers. Gavving and Minya joined him. They moved toward the strangers.

There were four on the trunk now: a girl, the man, and the older woman with her coughing burden. Rather watched Clave take the burned man’s line, hurl a sine wave across the one-winged girl’s torso, and pull her in.

“Looks okay,” the Scientist murmured.

Clave looked up and waved. Jeffer nodded and set the CARM moving. “It’s all right,” he said. “They sure don’t look dangerous. I wonder what happened to them? Where are they now?”

“I never saw strangers before,” Jill said. “I don’t know what to think.”

“That burning tree is still coming at us,” Rather said.

Jeffer nodded. The CARM surged, turning.

Black smoke wreathed the middle section of the tree.

Flame glowed sluggishly from within, illuminating blurred curves and oblongs. Debby said, “There’s stuff in the fire. Made stuff, machinery. It’ll burn up.”

That was knowledge burning in the core of the fire.

Jeffer hated what he had to say. “We can’t save it. If we had Mark and the silver suit…no. That might burn even him.”

“You’re not taking us into the fire?”

“We can push anywhere. The tide will hold the tree straight.” Jeffer had already taken them below the inward limit of the firecloud, where a black plume drifted east.

The CARM was passing north of the trunk. Jeffer tapped: the CARM turned. “It’s still dangerous. The tree could come apart while we’re on it.”

He moved in on the trunk. The bow grated against bark; Jeffer’s crew surged forward against their elastic bands. “I think the CARM was built for pushing,” he said. He tapped a blue dash in the center of the panel, and the whisper of power became a whistling roar. Tide surged against his back.