They reached the top of the ramp. Hastily, with both forest people bearing their weapons in their hands, they made for the Lock down which Uvarov had been carried.

As they approached the Lock, they slowed, almost as if synchronized. The three of them — Arrow Maker, Morrow and Spinner — stood and stared at the Lock.

Uvarov twisted his face to left and right. “Tell me what’s wrong. It’s the Lock, isn’t it?”

“Yes.” Morrow stepped forward cautiously. “Yes, it’s the Lock.” The cylinder of metal had been burst open, somewhere near its center; bits of its fabric, twisted, scorched, none larger than his hand, lay scattered across the Deck surface. There was a stink of smoke and fire — presumably Uvarov’s cordite.

Arrow Maker stood clutching his bow, open-mouthed, impotent. Spinner ran off toward the next Lock, her bare feet padding against the metal floor.

Uvarov nodded. “Simple and effective. We should have expected this.”

Morrow bent to pick up a piece of hull metal; but the twisted, scorched fragment was still hot, and he withdrew his fingers hastily.

Spinner came running back. She looked breathless, wide-eyed and very young; she stood close to her father and clutched his arm. “The next Lock’s been blown out as well. I think they all have. The Locks are impassable. We can’t get home.”

Uvarov whispered, “We should check. But I am sure she is right.”

Morrow slammed his fist into his palm. “Why? I just don’t understand. Why this destruction — this waste?”

“I told you why,” Uvarov said evenly. “The existence of the upper level was an unacceptable challenge to the mindset of Milpitas and the rest of your damn Planners. I doubt if they will have done any damage to the forest Deck itself. Sealing it off — sealing it away from themselves, apparently forever — should do the trick just as well.”

“But that’s insane,” Morrow protested.

Uvarov hissed, “No one ever said it wasn’t. We’re human beings. What do you expect?”

Arrow Maker paced about the floor. Morrow became aware, nervously, of the muscles in the back of the little man which flexed, angrily; Maker’s face paint flared. “Whether it was intended or not, we’re trapped here. We’re in real danger. Now, what in Lethe are we going to do?”

Morrow’s fear seemed to have been burned out of him by his anger at the foolishness, the wastefulness of the destruction of the Locks. “I’ll help you. I’ll not abandon you. I’ll take you to my home — I live alone; you can hide there. Later, perhaps we can find some way to open up a Lock again, and — ”

Arrow Maker looked grateful; but before he could speak Uvarov wheeled forward.

“No. We won’t be going back to the forest.”

Arrow Maker said, “But, Uvarov — ”

“Nothing’s changed.” Uvarov turned his blind face from side to side. “Don’t you see that? Arrow Maker, you saw the stars yourself. The ship’s journey is over. And we have to go on.”

Spinner clutched at her father’s arm. “Go on? Where?”

“Regardless of the reaction of these damn fool survivalists, we will continue. Down through these Decks, and onwards… On to the Interface itself.”

Arrow Maker, Spinner and Morrow exchanged stricken glances.

Uvarov tilted back his head, exposing his bony throat. “We’ve traveled across five million years, Arrow Maker,” he whispered. “Five million years… Now it’s time to go home.”

She shivered. Suddenly, she felt oddly cold.

Cold? No. Come on, Lieserl, think.

Sometimes her Virtual-human illusory form was a hindrance; it caused her to anthropomorphize genuine experiences.

Something had happened to her just now; somehow her environment had changed. How?

There it came again — that deep, inner stab of illusory cold.

She looked down at herself.

A ghost-form — a photino bird — emerged from her Virtual stomach, and flew away on its orbit around the Sun. Another came through her legs; still more through her arms and chest — and at last, one bird flew through her head, the place where she resided. Her cold feeling was a reaction to the slivers of energy the birds took away from her as they passed through.

Before, the photino birds had avoided her; presumably residually aware of her, they’d adjusted their trajectories to sweep around her. Now, though, they seemed to be doing quite the opposite. They seemed to be aiming at her, veering from their paths so that they deliberately passed through her.

She felt like screaming — struggling, beating away these creatures with her fists.

Much good that will do. She forced herself to remain still, to observe, to wait.

Behind her the birds seemed to be gathering into a new formation: a cone with herself at the apex, a cone into which they streamed.

Could they damage me? Kill me, even?

Well, could they? Dark matter could interact with baryonic to a limited extent. If their density, around her, grew high enough — if the rate of interaction between the birds and the particles which comprised her grew high enough — then, she realized, the birds could do anything.

And there wasn’t a damn thing she could do about it; embedded in this mush of plasma, she could never get away from them in time.

She felt as if a hard, needle rain were sleeting through her. It was uncomfortable — tingling — but not truly painful, she realized slowly.

Maybe they didn’t mean to destroy her, she wondered drowsily. Maybe — maybe they were trying to understand her…

She held out her arms and submitted herself to inspection by the photino birds.

They formed into a rough column — Arrow Maker leading, then Uvarov, followed by Morrow and Spinner-of-Rope, with Spinner occasionally boosting Uvarov’s chair.

Morrow stepped over the ramp’s shallow lip and began the gentle, hundred-yard descent back into the comparative brightness and warmth of Deck Two.

“Listen to me,” Garry Uvarov rasped. “We’re at the top of the lifedome. We have to get to the bottom of the dome, about a mile below us. Then we’ll need to find a pod and traverse half the length of the Northern’s spine, toward the drive unit; and that’s where we’ll find the Interface. Got that?”

Most of this was unimaginable to Morrow. He tried to concentrate on the part he understood. “What do you mean by the bottom of the lifedome? Deck Four?”

A bark of laughter from Uvarov. “No; I mean the loading bay. Below Deck Fifteen.”

Morrow felt something cringe within him. I’m too old for this… “But, Uvarov, there is nothing below Deck Four — ”

“Don’t be so damn stupid, man.”

“…I mean, nothing inhabited. Even Deck Four is just used as a mine.” He tried to imagine descending below the gloomy, cavernous Deck in which he’d spent so much of his working life. It might be airless down there. And it would certainly be dark. And -

There was a whisper of air past his ear, a clatter as something hit the metal of the ramp behind him.

Arrow Maker froze, reaching for his bow instantly. Spinner hauled Uvarov’s chair to a halt, and the old doctor stared around with his sightless eyes.

“What was that?” Uvarov snapped.

Morrow took a couple of steps back up the ramp and searched the surface. Soon he spied the glint of metal. He bent to pick up the little artifact.

It was a piton, he realized — a simple design he’d turned out hundreds of times himself, in the workshops of Deck Four, for the trade with the forest folk. Perhaps Arrow Maker and Spinner had pitons just like this in their kit even now.

But this piton seemed to have been sharpened; its point gleamed with rough, planed surfaces…

There was another whisper of air.

Spinner cried out. She clutched her left arm and bent forward, tumbling slowly to the Deck.