"I'm not leaving Fabian. Not if tekmercs are on their way here."

Fabian looked up at her with complete adoration. Greg realized they weren't going to be separated. And he had promised Jason Whitehurst exactly that. Bloody wonderful.

"We're not asking you to leave him, Charlotte," Julia said gently. "One moment."

There was a burst of static.

Jason Whitehurst's voice came out of the music deck speakers. "Fabian?"

"Yes, Father?"

Greg's cybofax bleeped. He looked down at it.

"You stay with Charlotte and Mr. Mandel," Jason Whitehurst said. "It'll be a lot safer for you. These damn tekmercs are all over the old Colonel. Bloody trigger happy brutes, they are. I'll catch up with you later, I must see the crew is all right first, noblesse oblige, and all that. You understand that, don't you?"

"Yes, Father."

Greg showed the cybofax to Suzi. Her face remained impassive as she read the screen's message.

"Splendid chap; bit of an adventure for you. Charlotte, my dear girl, what can one say? I'm most dreadfully sorry about all this trouble. Julia will explain later. You take care of Fabian in the mean time for me, yes?"

"Yes, sir."

"Jolly good."

Greg pulled a first aid box off the wall, and found a local anaesthetic infuser. Charlotte didn't resist when he took her hand. He pressed the infuser tube to her wrist.

She gave a tremulous little sigh as the anaesthetic took effect.

"Careful you don't knock the hand against anything," he warned her.

She nodded meekly.

Suzi was wiping Fabian's chin with a disinfectant tissue.

"OK," Greg said. "Let's move. Julia, which way?"

"Turn right outside, down to the hull, then head up towards the prow. I've loaded your route."

He glanced at the cybofax, memorizing the Colonel Maitland's blueprint with its superimposed red line.

It was cool outside the MHD chamber. The engineering bay heat exchangers constantly circulated the air in the gap between the hull and the gasbags, preventing the helium from becoming superheated and losing lift capacity. Greg thought it smelt vaguely of chlorine. It left an unpleasant tang at the back of his throat.

He led them along the walkway, the opposite direction to the way he and Suzi had come. Charlotte and Fabian followed him, holding hands; Suzi brought up the rear. The worst of his neurohormone hangover was lifting, but he wouldn't be able to use the gland again today, not after two psi effusions like that.

"Greg, a little faster, please," Julia said out of his cybofax. There was an edge in her voice.

"Right." He began to step out.

A rip gun was fired behind them, the sound of its shot rumbling round the engineering bay. It was the signal for a whole barrage to begin.

"What's that?" Charlotte asked, raising her voice above the clamour.

"Rip guns."

"Crikey," said Fabian, he squinted at Greg with his one good eye. "You mean a neutral-beam weapon?"

"No messing."

They reached the hull. A silent rank of drones was drawn up beside the transverse frame ladder. Greg didn't have time to question their presence. He turned on to the walkway that led towards the prow, sandwiched between the gasbag and the solar cell envelope. It curved away ahead of him, fading to grey.

The rip guns had stopped firing.

"Get going," Julia said. The drones began to move out on to the engineering bay girders.

Fabian watched them go curiously. "Do you have hotrods working for Event Horizon?" he asked.

"One or two," Julia answered.

"Fabian, not now," Charlotte said.

"Sorry."

The walkway made Greg think of the eidolonic loop he'd left Chad in. The engineering bay had disappeared from sight behind, and more walkway kept unfolding in front, seemingly endless. They were moving at a jog now. Charlotte's panting was loud in his ears. His own breathing wasn't too good either.

There were five rip-gun shots fired in rapid succession. The sound barely audible.

"Last of the drones gone," Julia said. The cybofax wafer was in his top pocket again, banging on his chest. "The three tekmercs are covering all the options. One has gone down the transverse frame ladder, another is climbing up."

"And the third's coming after us," Suzi finished.

"Right," said Julia.

"Run faster?" Greg asked.

"He'll still be able to catch you. You're only a hundred and eighty metres ahead of him."

"The next transverse ladder?"

"No, you'd be sitting ducks on that."

"Stand and fight. The Tokarev might penetrate the armour."

"No," Julia said. "I've got your escape route mapped out. Keep going, twenty metres. Stop by the next doughnut gasbag."

The only way Greg found it was because of the deep concave fold in the plastic where the two bags pressed together. He came to a halt, breathing hard. Charlotte stopped behind him, her face drained.

"Are you all right?" she asked Fabian.

The boy flipped some of his ragged hair off his face. "Yes." They still hadn't let go of each other's hands.

"What now?" Greg asked. He kept his nerves alert for the sound of the tekmerc, wondering if he should order another gland secretion after all.

"Start hyperventilating," Julia said.

"What's this bollocks, you hustle us along here for exercise classes?" Suzi snapped. "Have you glitched?" She was the only one who wasn't breathing heavily.

"No, listen," Julia said. "I want Greg to slice open the doughnut gasbag with his Tokarev. Then you hold your breath, and slide down the inside. You will stop right above the keel walkway. Greg cuts the plastic again, and you drop out.,

Suzi gave Greg an imploring look. "If both of us fire at once, we can snuff that tekmerc."

Greg wasn't so sure. Suzi's idea was all down to chance. Julia's had logic behind it. Machine logic, admittedly. And of course, she didn't have to do it herself.

"The tekmerc can just follow us down the doughnut," he said.

"No," Julia said. "It'll tear like paper under the weight of the armour. He'd fall straight out of the airship."

"All right, we'll try it."

"Shit," Suzi said. "Fluid."

Greg looked at Charlotte and Fabian. "Do you two understand?"

They both nodded, both looked scared.

"Whatever you do, don't breathe in while you're inside the doughnut," Julia said. "Helium isn't toxic, but there's no oxygen. You'll asphyxiate."

Greg got his breathing back under control, and drew the Tokarev. "Everybody ready?"

"Do it," Suzi said.

He aimed at a point level with his own head. "Breathe in now, and follow me straight away." He hoped to hell the two kids would do as they were told, Suzi would have trouble bullying both of them. Or maybe not.

The vivid red beam pierced the plastic, and Greg swung it down to the walkway, opening up a two-metre slit. With the Tokarev held in his right hand, he sat on the walkway grid, pushing his feet into the open gash. The blackness inside the doughnut was impenetrable, it almost seemed to slop out on to the walkway. He ducked his head under the hand rail, and pushed off.

The Messerschmitt exploded without warning. Julia had to replay the external camera memories to understand the sequence of events.

Two Typhoon air-superiority fighters arrowed in from the north, silver-grey needles with wings retracted, using the airship as a radar shield. Not that the Messerschmitt would have had many options even if it had detected them, not when they travelled at Mach eleven. One went over the Colonel Maitland, the second went under. Three Kinetic Energy Kill missiles slammed into the Messerschmitt at Mach seventeen. Then the fighters were gone.

A fireball enveloped the Messerschmitt, billowing out. It was slapped by the supersonic backwash from the two fighters; invisible hands compressing it back into a lenticular shape. Chunks of flaming wreckage spewed out from the ragged edges, spinning through the air, arching down towards the distant ocean.