London didn't go in pursuit of Salthook for another three days. The town had been gnawing at a coal seam when Valentine flew past it on his 13th Floor Elevator and his sage advice to Mayor Chrome was to let it stock up on the fuel before London went hunting for it. But when the chase finally happened it was a moment of great excitement for Londoners starved of such adrenaline. The engines and auxiliaries throbbed from deep below, deck plates rattled and museum exhibits shook off their dust as the city hurtled along at a mind-blowing speed of seventy miles per hour!

Tom Natsworthy had been cleaning the ancient exhibits when the chase started. He longed to go and watch with the rest of London, but was denied by senior Guildsman Chudleigh Pomeroy. Not to be deterred, Tom made the defiant decision to slip out just for half an hour. He'd be back before anyone knew it.

It was decision that would change his life.

A row with a First Class Apprentice followed, after the fool had insulted Tom's dead parents, a fight had broken out and Tom had stumbled right into the hefty frame of Pomeroy. Gut Duty was handed out as punishment, and Tom was delighted to be making the rounds with Valentine, as they dissected the catch of Salthook. Tom also met Katherine Valentine and her Dog, immediately deciding that all the girls he rescued in his daydreams from now on would be the beautiful daughter of the Head Historian.

But then came the drama. A young girl, no older than Tom, attempted to murder Valentine. Tom stepped in to save his idol, seeing his chance to be the hero of the hour, as he chased the assassin through the heat and smoke of the Gut. He pursued her across catwalks and steel bridges, around the huge boilers and right back to the waste chutes.

That's when he saw her face. Mangled, ruined, a hideous girl who looked like a portrait someone had furiously crossed out. And the claims she made! She said Valentine did it to her! Tom decided that was impossible. Valentine was good and brave and kind, he'd never do such a thing ...

"Ask him!" the hideous girl had shrieked. "Ask your hero what he did to Hester Shaw!"

Then a stray crossbow bolt from one of London's Police Bobbies struck Hester just above the knee. She collapsed and whined from the agony. Tom didn't feel like much of a hero anymore, just sorry for this repulsively scarred girl, and searingly guilty for being the one who had trapped her in this situation. He wanted to help her, but she climbed up onto the railing of a waste chute and pitched herself over before Tom could think to react.

"I couldn't stop her," Tom moaned as the crowd caught up to them, Valentine at the head of the queue. "She just jumped ... right to her death."

"It's alright, Tom," Valentine had soothed. "You did all that you could. You aren't to blame. But tell me something ... did you see her face?"

Tom hadn't known what to say, what to confess. So he simply nodded and said that the girl had told him her name was Hester Shaw.

"Great Quirke!" Valentine had hissed, before muttering an apology ... and pushing Tom right out of London after the girl with the ruined face ...

Harry and Hermione had no idea about any of the incredible events taking place aboard their home city. They had taken possession of The Jily Harmony the day before London's chase of Salthook had begun, and were now in the skies above the Earth, miles and miles away by the time any of that happened.

Harry did most of the early piloting, as Hermione was cross and uncomfortable on account of her new Guild tattoo still being quite sore between her eyebrows. She was so grouchy about it that in the end Harry set the controls to autopilot, before spending a good deal of time trying to kiss the soreness better. This led to deeper kisses, roaming hands ... and the first steamy air ever to hit the windows of The Jily's gondola.

It would be far from the last time that this happened.

So in the quiet solitude of the sky, with no-one around to hear or snicker, Harry and Hermione retreated to their double-birth cabin and christened their new bedroom, letting their passions run away with them until they were left sweaty and shivery, with a contented breathlessness that neither felt they would ever get tired of sharing together.

At some point, however, they had to get back to their navigating.

"Tea?" Hermione offered, proffering a steaming mug towards Harry, as he sat in the pilot's seat and admired the view.

"Thanks," Harry grinned, taking the tea with one hand and reaching under his scarlet -trimmed black Guildrobe with the other. It was a robe which Hermione had flung over her own shoulders and was all that she was wearing, allowing Harry to give his girlfriend's peachy behind a good squeeze.

"Oi, cheeky!" Hermione admonished falsely. "I need my bum to sit down if you don't mind!"

"I'm happy for you to stand," Harry quirked, caressing the soft flesh beneath his fingers.

"As am I, but my knees are still a bit shaky," Hermione purred, running her hand through Harry's still-damp hair as he tugged her warm body a little closer.

"Still not loving the height?" Harry asked.

"It wasn't so bad ... when I was on my back," Hermione returned vampishly. "But my knees were shaky enough from all that ... this isn't exactly helping."

"Take a seat then," Harry suggested, finally removing his hand. "Flying really is the safest way to travel, you know. There's no-one to eat us up here."

"No, but there are air-pirates and birds and gunships from the Anti-Traction League," Hermione fretted. "Safe is a relative thing, Harry."

He turned to her in his seat. "Hey, becoming aviators was your idea, if I remember rightly!"

"It was," Hermione agreed sniffily. "How else are we going to become great archaeologists if we haven't got an airship to get to far away places? I just wish there was another way."

"Such as?"

"Well, imagine being able to just disappear in one place and reappear instantly in another," Hermione replied. "That would be just perfect for me."

Harry pulled a face at her. "You've been reading that book again, haven't you? Is there a spell for teleportation in there or something?"

"I can't read the book, as you well know," Hermione huffed, frustrated by the fact. "Finding out that it is written in a runic script is all very well, but the knowledge of how to properly interpret the runes is long lost in time. If only I had some way to decode it."

"Why is it so hard to work out?"

"Runic script is notoriously difficult to interpret, because each rune has many meanings," Hermione began. "But the order and position in which they appear in a horizontal row with other runes, and those other runes themselves, changes the interpretation. Without knowing all the meanings and all the combinations, I may never be able to decipher Hogwarts, A History."

"Have faith, I'm sure you will," Harry told her supportively. "You're the cleverest person I know. If anyone can work this out it will be you."

"Thanks," Hermione smiled. "I just wish I could find a reference point by which to start."

"Maybe you'll unearth one at our first stop. You never know."

"Where are we going then? I don't remember us settling on a first location."

Harry laughed at that. "What? You thought I'd just aimed The Jily for the second star to the right and headed straight on till morning!?"

"Well ... sort of, yes!" Hermione confessed with a giggle. "You're not usually the one who comes up with a plan. So, where are we going?"

"I thought we'd go straight to Airhaven," Harry revealed. "If we are to become the newest addition to the skies, that's the best place to put our faces and services about. They have all sorts of shops and traders passing through up there. Maybe we'll find you a dusty old book on runes somewhere amongst the jumble."

"Ooh, Airhaven! Good choice!" Hermione chirped. She'd been looking forward to seeing the famous city in the sky again, the only Traction City that flew rather than rolled around on the Earth. What better way to avoid predator cities than to float a few thousand feet above them? "When will we get there?"

"Not till tomorrow evening at the earliest, and that's assuming we have a fair wind behind us," Harry replied, consulting the little Goggle-screen that was giving him up-to-date weather reports. "We'll be spending the night in the sky, Hermione."

"Oh, that's going to be so romantic!" Hermione swooned, reaching over to squeeze Harry's forearm. "All the stars, the moonlight ... I cant wait!"

Airhaven was one of the most famous of all Traction Era towns. After escaping to the sky, it became a haven and meeting post for aviators and sky traders alike, its brightly coloured gasbags supporting a single tier of light alloy as it hung safely over the Great Hunting Ground. It would drift there all Summer, before heading south in Winter to warmer skies. Harry remembered it once hanging over London for a whole week and he took Hermione on a sight-seeing balloon to visit it for one of their early dates, though he couldn't recall which number it was.

But he did remember that it was the first time she had kissed him on the mouth.

Harry smiled to himself as he drank in the memory. He looked over at Hermione, curled up and dozing in the co-pilot's chair with a blanket around her shoulders. She looked so at peace when she slept, when that little crinkle of concentration that she always wore during their school hours relaxed back into her glowing skin. It would be forever hidden beneath the blue eye of their Guild tattoo now, the eye that always looked backwards into time.

For now, though, it was a time to look forwards, to the bright and exciting future that stretched out before them. Hermione stirred gently as the warble of Airhaven's homing beacon crackled over the radio, Harry requested permission to dock at the air-quay like a seasoned aviator, then guided The Jily Harmony through a drifting cloud bank into docking strut Number Seven, all under the watchful eye of the harbour officers in their sky-blue livery.

As soon as the mooring clamps were engaged, Harry and Hermione prepared to disembark. It was nice and warm above the clouds, with a late afternoon sun glinting off the shiny plate decks of the floating town. Harry locked The Jily's gondola hatch and safely stowed the key around his neck, waved cheerily at a gaggle of airship-spotters, who were busy taking down The Jily's registration number, then allowed Hermione to take his hand and lead him into Airhaven proper.

Their first stop was the harbourmaster's office. Big signs read things like NO SMOKING! TURN OFF ALL ELECTRICS and NO SPARKS!, while a loudspeaker boomed out these warnings to unsuspecting passers-by outside the office doors, too. Sparks were the constant fear of the air-trade, on account of the danger that they might ignite the flammable gas in the envelopes of airships. Even over vigorous hair-brushing was a serious crime here, which made Hermione very cross at having to return her own brush to The Jily, for she had masses of bushy hair which needed regular attention to stop it from misbehaving.

Then Harry and Hermione had to produce their licence and registration papers, to prove that they owned their airship, as well as a certificate of their medical status to confirm that they had no history of spontaneous combustion in either of their families. Once they had convinced the harbourmaster that they weren't about to burst into flames at any moment, they were free to go about their business.

That business took them to the single thoroughfare that ran like a hoop around Airhaven. It was full of shops and stalls, chandleries, cafes and air-trader's hotels. Harry looked around in awe, trying to take in everything at once so that he might remember it forever. Turbines and ventilators whirred above every building, mechanics crawled spider-like over the huge engine pods, and the air was alive with the smell of foreign food and the mixed languages of Anglish, Chinese and Airsperanto.

"Ooh, Harry, let's have dinner! I'm starving," Hermione whispered, clinging onto Harry as she, too, tried to absorb the exotic environment all around them. "Let's go to the Gasbag!"

At the curve of the High Street was a famous inn called the Gasbag and Gondola. It was made from the repurposed old hull of a retired sky-clipper, and its walls were adorned with pictures in chipped enamel frames, showing balloons and Zeppelins and all manner of sky vessels, including the heavier-than-air flying machines that the Ancients had built, called aeroplanes. The secrets of their construction, as with so much from before the Sixty Minute War, had long since been lost and no-one knew how to build them anymore, though the awe that humans were capable of such genius continued to inspire generations of aviators and aviatrixes alike.

Many of those aeronauts were packed into the narrow booths of The Gasbag this evening. They strode by with careless confidence, their long coats fluttering behind them like leathery wings. Harry and Hermione slid into a free booth, with emerald green seats, and placed orders with a waitress who came by on roller skates. Then they waited and listened to the curious talk from the booth opposite.

And what startling talk it was.

"Valentine, yes, that's what I heard," a young African aviator was saying as he sipped on his drink. "Someone tried to kill him!"

Harry snapped his head to Hermione, her look of wide-eyed shock matching his own.

"Pity they didn't succeed," a woman replied. She wore dark glasses and had long glossy hair. She might have been Malay or Tibetan, or a beautiful secret agent from Shan Guo, but her face was half-hidden by her glasses and a silk shawl that she wore high on her neck. "I shall have to make an offering to the God of the Aviators for the next attempt to be more successful. But what became of the assassin, Khora?"

Khora, who was the intense, courageous Captain of the gunship, Mokele Mbembe, turned his eyes sharply.

"Killed. Dived out of a waste chute, but she'd been shot and would have likely bled out anyway," Khora replied blandly. He sounded like he didn't much care either way. "I did hear that some young kid died with her. Some Apprentice Historian. He was trying to catch her, but then Valentine caught up with him and whoops ... pushed him out of the chute after the assassin."

Harry blinked hard at Hermione as they listened to the story, dying for more details, but without the courage to ask this fierce soldier. Captain Khora didn't seem to be much older in age than they, but he was clearly far more worldly and hardened.

The woman leant in close to her companion. "Valentine killed the boy, you say? But why?"

"Must have been something about the girl, Feng Hua," Khora mused to the aviatrix, who was called Anna Fang, but was often referred to by this affectionate nickname, which meant Wind Flower. "She must have had previous with Valentine to have wanted to kill him, but it's obviously something he didn't want getting out. So if the boy knew anything about the assassin, he and his secrets had to be sent to their graves, too. Valentine is known for liking to make a clean job of his murders."

"Interesting," said Anna Fang, rubbing her chin thoughtfully. "And they were definitely dead?"

"Probably," Khora huffed, dryly. "Jumping out of a rolling mountain's waste chute at high speed is never usually good for one's health."

"But we aren't sure?"

"I doubt Valentine went back for the bodies," Khora scoffed.

"Then they could be alive," Anna Fang continued, as if to herself. "And they might know something important about Valentine, something we can use."

"What are you thinking?"

"I'm going to leave, tonight, take The Jenny Haniver andsee if I can find some trace of them," Anna Fang announced. "There's not much chance that they're alive, but as long as the possibility exists then Valentine will be hunting them. I know how ruthless London's greatest secret agent is, and he wont stop until he knows for sure ... we can only hope that I can get to these kids first."

"So what will you do?" asked Khora.

"If they survived, they might be trekking on foot through the Out-Country, or a rogue town might have picked them up," Anna Fang began. "If they are huddling in London's caterpillar tracks, I'll find them. If they've been found by a rogue town, they might be safe and I'll bargain for them."

"And if they've wound up being taken to a trading cluster to be sold as slaves? What then?"

Anna Fang tipped the lenses of her dark glasses down to reveal even darker eyes, sparkling with a fiercer expression than even Khora could have conjured. "If that's the case, then I'll rescue them and bring them here ... and we'll deal with the body count at a later date. This might be the break we've been waiting for, Khora."

"That sounds dangerous, let me come with you," Khora offered with his trademark steel and bravery. "I wont let you go into danger alone, Feng Hua."

"You know, if I was fifteen years younger, I'd have fallen so badly for you, Khora," Anna Fang replied with sincere affection, reaching over to stroke Khora's cheek. "But no, I will go alone. You must go on to Batmunkh Gompa and relay this news there. Perhaps someone else can make sense of it. Do not fret, I can take care of myself."

Anna Fang drummed her thumb on the hilt of the slim sword at her hip, then danced her fingertips across the array of daggers in her belt.

"The whole air-trade knows that, Anna," Khora smiled. "Just promise me you'll come back in one piece."

"I always try," Anna Fang nodded back as she stood to leave. "Now ... what was the name of the assassin and her lost boy?"

"The girl we don't know, but the boy was some lowly Apprentice," Khora revealed. "His name was Not worthy? Noteworthy? Something like that."

Harry turned to Hermione and hissed under his breath. "Natsworthy! Hermione ... Valentine tried to murder young Tom! He pushed him out of London after this girl assassin failed to kill him! We have to go back, too, and see if we can find them."

"I don't think we can do any better than that Anna woman," Hermione whispered back firmly. "She seems to know the lay of the land and sky better than us. No, Harry I think we're better off here. Let's wait a few days and see what happens. After all, Tom might want to get back to London if he gets rescued. Just think how great would it be for him to find us here to give him a lift home!"

"I suppose you're right," Harry conceded. "Okay, we'll do it your way. But if Anna Fang hasn't brought Tom here within the next three days, we'll be going after him ourselves."