And then, as suddenly as they had appeared, the creatures were gone. "What in the name of—?"

"I'll be damned," Bronski said. "It worked."

Frowning, Cavanagh turned his head. The herd of grooma had gathered on the vine mesh directly above where all three Bhurtala were now standing, screaming and clawing viciously at the lead Bhurt as he struggled against their attacks to pull himself up by the hanging vine loop.

The hanging vine loop that Bronski had fired three flechettes into, cutting into the Parra vine with sharp-edged metal, and sparking precisely this reaction from the vine and its grooma symbionts. "That's not going to hold them for long," Cavanagh said.

"I know," Bronski said, already clambering carefully back to his feet. "Maybe it'll be long enough."

Grimacing, Cavanagh eased one leg up—

And dropped abruptly back into a sitting position as something tore through the outrigger branches and went whizzing past his ear.

"Watch it!" Bronski snapped, flailing his arms for balance. "Stay down!"

Cavanagh dropped his torso to the vine, wrapping his arms around it and looking back. The two Bhurtala still on the roof, not content to wait for their climbing partner to clear away the enraged grooma, were running across the rooftop toward the two humans, jagged pieces of something clutched in their huge hands. Even as Cavanagh watched, one of them hurled one of the pieces upward.

This one came closer, ricocheting off the vine just behind where Cavanagh was sitting. "They're trying to knock us off," Bronski snarled. "Using pieces from the trapdoor."

"What do we do?"

"You just hang on." Dropping into a crouch on the vine, Bronski swung his flechette pistol around and began firing.

For all the effect, he might as well have been throwing snowballs. The jagged missiles kept coming, swishing through the leaves or bouncing painfully off his legs or arms. One piece caught Bronski square on the chest, and he flailed madly for a heart-stopping minute before he managed to regain his balance.

And then, as abruptly as it had started, the barrage was over. Cautiously, Cavanagh leaned his head around the vine he was clinging to and looked down.

One of the Bhurtala was loping back toward the ruined stairway entrance. The second was crouched down below them, digging with his hands at the edge of the roof.

"He's ripping out pieces of wood," Bronski said quietly. "Getting more stuff to throw at us."

And even if he didn't succeed, the Bhurt heading back to the stairway was bound to find more ammunition. And then the two of them would resume the aerial attack, keeping the two humans pinned down until their friend hanging from the vine cleared away the grooma and climbed up.

At which point he and Bronski would be dead.

Cavanagh swallowed, his mouth chalk dry, his pulse racing painfully in his throat. The aliens' scenario was vacuum clear, as inevitable and unstoppable as an incoming tide. And it left them with exactly one option. "Then we have to go right now," he said to Bronski, his voice shaking with dread. "And we have to run."

"I know," Bronski said. Had probably known, in fact, long before Cavanagh had. "You think you're up to it?"

From beneath them came the sudden crack of breaking wood. "Do I have a choice?" Cavanagh snarled back, unlocking his ankles from around the vine and shoving himself to his feet again. "Come on."

He set off along the vine, his careful jogging pace quickly and inexplicably accelerating into a flat-out run as adrenaline or fatigued recklessness or sheer hubris flooded into him. Time seemed to slow to a crawl, his vision tunneling in to block out everything except the vine ahead, the strange madness ruthlessly crowding out any attempt by his rational mind to pause and think any of this through. Beneath his feet the rooftop dropped abruptly away to the lights and insectlike scurrying of pedestrians in the street below; behind him the sudden howling of their pursuers was grimly satisfying proof that they'd been caught off guard. A fresh pair of wooden chunks went spinning past, too late and far too wide of the mark. Cavanagh kept running, dimly noticing that his cheeks were hurting—

"Hold it," a panting voice called. "Cavanagh—hold it."

Cavanagh jerked, coming suddenly aware again of Bronski running beside him. Suddenly aware, too, that the ache in his cheeks was due to a wide, almost feral grin laminated across his face. "What?"

"I said stop, damn it," Bronski growled, coming to a teetering halt and jabbing a finger downward. "Look—we're here."

Cavanagh frowned, looking down. The street he'd last noticed himself running over was gone. In its place, barely two meters beneath his feet, was another roof. "Oh."

"Oh?" Bronski puffed, easing into a crouch and sitting down on the vine. "Is that all you can say, oh? I yelled for you to stop a whole building ago."

"You what?" Cavanagh blinked, sitting down on the vine and looking behind them. The brigadier was right: the rooftop directly behind them—a small roof, just beyond a narrow, dark alleyway—was indeed not the one they'd left from. That particular roof was one building farther back. "I'll be damned."

"I thought for a minute you were going to run all the way to the spaceport," Bronski grunted. Getting a grip on one of the tendrils, he slid off the vine, hanging for a second before dropping the rest of the way. "Damnedest switchover I ever saw. I didn't know you Brits did this berserker rage thing."

"Must be the Scandinavian blood in the family line," Cavanagh said, still not believing it as he followed the brigadier down onto the roof. "I don't think that's ever happened to me before."

"Well, don't lose the cutting edge just yet," Bronski warned, working at the edge of a shiny square in the roof with a folding knife. "In case you hadn't noticed, the Bhurtala aren't just sitting there waiting for us to come back."

Cavanagh looked around again. The grooma were still gathered around the damaged tendril, their chattering clearly audible over the city noise coming from below. But the Bhurtala themselves were nowhere in sight. "They must have gone back down to street level."

"Brilliant deduction, Holmes." There was a soft click, and Bronski pulled up the trapdoor. "If we're lucky, maybe they left before they saw which building we wound up on. Let's go."

No one was waiting for them as they emerged from the stairway onto a deserted side street. "Any idea where we are?" Cavanagh asked, looking around. Two blocks ahead he could see one of the more brightly lit major arteries, though even at their distance it was clear that the earlier crush of pedestrian traffic still hadn't resumed.

"Bokamba's place is about a block that way, I think," Bronski said, pointing in a direction roughly parallel to the main street. "The Puerto Simone street system is an inhumane joke, but I think if we go this way, we'll hit a tram line that'll get us to the spaceport."

"I hope it's not far," Cavanagh said, rubbing his sleeve at the sticky sweat around his neck. His berserker rage, as Bronski called it, had worn off on the walk down the stairway, leaving him a throbbing collection of sore joints, exhausted muscles, and aching bruises where the grooma and the Bhurtala's wooden missiles had struck him. "I don't think I could walk more than another—"

And from behind them came an all-too-familiar roar.

Cavanagh spun around. A block away, in the gloom of the side street, stood the dark figure of a Bhurt, its arms raised in triumph. It howled again, this time in a call of summons.

"Come on," Bronski snapped, slapping Cavanagh's shoulder for emphasis and taking off in the opposite direction.

"We can't outrun them," Cavanagh protested as he broke into a sprint, his aches and exhaustion pushed to the background by a fresh surge of adrenaline.