—Until one message to the Rook caused the duty officer to curse under his breath. Reluctantly, he sent Martor to knock on the admiral's door.

Hayden Griffin was drifting in a timeless haze of pleasure in Aubri Mahallan's arms when the Rook shook from some sort of collision. They were both instantly awake. There was another bump and then the grating sound of hull-against-hull contact. Hayden heard shouting.

Aubri's eyes were wide. "We're being boarded!"

He shook his head. "No gunshots. Something's up, though."They both hastily dressed. "Stay here," he said. "It might be the Gehellens after all."

She shuddered. "If we really are being boarded, I'm going out the window this time."

He flipped out the doorway and closed the portal, immediately encountering Martor. "Come on!" shouted the boy. "We're taking on passengers." He bounded back toward the hangar.

The Rook and the Unseen Hand were lashed together, door to door. The ships bucked and strained against the ropes and wind whined through the gap. Men were leaping between the ships carrying boxes and rockets. The Rook's new boatswain yelled and pointed, face red and sweating, as crates and bedrolls bounced and tumbled through the air.

"What's going on?" Hayden asked one of the Unseen Hand's crewmen. The man grimaced and waved at his ship.

"Oxygen system's busted. We'll suffocate if we take the Hand into that place right now. Admiral ordered us to transfer over to the Rook, leave a skeleton crew on board. with fewer people breathing over there, they might stand a chance." He looked around at the crowded interior of the Rook. "Where can I strap my bedroll?"

"Martor, take care of him," said Hayden. He headed for the hangar doors, intending to help with the transfer. Glancing forward between the ships, he was startled to see nothing but blackness ahead of them. "Where are we?"

"Hard to say," said one of the hatch gang. "Word is that it's too dark for sighting and we don't know the local navigation beacons. The sargasso could be ten miles away, or we might be about to run into it at full speed."

Hayden spent a few minutes jumping back and forth between the ships carrying supplies—crates of food, coils of rope, and rolls of canvas for the braking sails. He was untying a barrel of hydrogen peroxide near the back of the Hand when the shouting in the hold took on a hysterical edge.

"Cast off! Cast off! Just cut it!" Hayden let go of the barrel and bounded up to the Hand's hangar. Men were frantically slashing at the ropes that bound the two ships together. He opened his mouth to ask what he could do to help and was drowned out by the sound of both ships' collision horns going off. "Brace for impact!" someone screamed.

Something like a giant black claw swept through the narrow space between the ships. One crewman who had been jumping the gap was suddenly gone. At the same time, both ships lurched and a series of loud rattling bangs shook the Hand.

"We're in the trees!" They had reached Leaf's Choir; apparently the navigators had misjudged the distance after all. More bangs, rattles, and cracks signaled impacts with the charred branches of the former forest. The Hand shuddered and began to slow.

The gap between the ships suddenly expanded. Hayden realized he was holding tight to a beam aboard a vessel that had no oxygen supply. Everyone he knew was on board the Rook, including Aubri. In seconds they would be separated and he might never see her again.

He spun and put his feet against the beam. Looking up he saw the square of light that was Rook's open hangar door. Men crowded there, but only one was looking in his direction. It was Carrier.

For a moment he and Venera's servant locked gazes. Hayden saw Carrier hesitate—just for a second—and then he extended his hand.

Hayden jumped. For a second he was in turbulent air, surrounded by lashing black branches and the scent of charcoal. Then Carrier had him by the wrist and was pulling him into the Rook. The hatch gang cheered.

Carrier let go and turned away. The boatswain pushed Hayden toward the inner door while shouting, "Shut the hatch! Tar it! Stand by for sargasso running."

Hayden looked back as the hatch closed. Carrier had disappeared. Through the closing hatch he could see the lights of the Unseen Hand flickering through a chaos of whipping branches. The Hand veered away, its light guttered and was lost; then the hatch slammed shut and the gang moved to seal it.

They had reached Leaf's Choir.

MOST OF THE Gehellen vessels fell back to circle the black forest in frustration, but some sargasso-equipped ships continued to follow the Slipstreamers. This made it risky for the Rook to slow down—but it was equally risky to continue at speed. The outermost layers of Leaf's Choir had been picked over by charcoal harvesters for centuries, and now consisted mostly of long spearlike trunks, denuded of branches, that wove and curved through the air for hundreds of feet at a time. These spears could puncture the hull of even an armored warship, if struck at high speed.

Each tree had originally been rooted to a small clump of asteroidal dirt. As they grew they wound branches around one another, like swimmers grasping for companions. With no sense of up or down, the trees had used Candesce and the local suns as their targets, sending threadlike stalks and branches through the empty air, spreading nets of leaves to catch light and passing moisture. Gradually, they had formed a vast and diffuse substance that made its own weather, caught drifting dust and stones and assimilated them, and greedily sucked up the carbon dioxide and smoke of the industries that thrived among them. Humans had woven the pliable branches into elaborate structures, entire cities of living green that went on, chamber by beautiful breathing chamber, for miles. Generations of gardeners cultivated their home trees, adding flowers and liana. Giant spheres and rods of water filled the central spaces, cupped by a thousand delicate fronds, in which fish and people swam. The people of Leaf's Choir had cleverly fashioned gigantic mirrors out of water—simply by stretching nets and wetting them until the water clinging to neighboring strands met and merged into a single surface—and used these to reflect the light of Candesce and their own two suns many miles into the forest.

All of it had burned. All was now black and sunless, the air replaced by stagnant smoke that never settled, merely eddied and spiraled around itself in an eternal dance of mourning.

The ships' navigators soon started cracking under the strain of finding their way through this gargantuan, mazelike tomb. They spent hours staring out at the advancing lines of black lit by the ships' headlights. Odd objects would appear in the light and slide by like hallucinations: window lintels, blackened shoes, spoons, and bedposts. The men began to swear they saw figures beckoning to them from the darkness beyond the branches.

And all the while, the Gehellens followed.

Chaison Fanning locked himself in the chart room with Gridde and Aubri Mahallan. They compared photographs of the measureless spaces and distant, branching buttresses of forest growth to the charts Aubri had found in the library. The precious treasure map from the tourist station waited in a glass case beneath the chart table. "It all hinges on finding the city of Carlinth," Gridde said over and over. "Find the city, we can find the rest of the way. If we don't…"

There were reports of men collapsing suddenly. Unless the air was kept moving, carbon dioxide, monoxides, and smoke from outside seeped in and pooled. You could put your head into an invisible cloud of death without knowing and just pass out. It was as though some unseen monster stalked the ship. Everybody watched everybody; nobody slept unless their face was near a fan.