The bruised, purplish clouds looked like the coiled intestines of some enormous beast. A vast vortex had formed, circling slowly above Quentaris like a gigantic whirlpool turned upside-down. Thunder pealed. Lightning jagged, setting off ear-splitting detonations.

Everything began to shake. The vibration started deep in the earth beneath Quentaris, spread up through the rock on which the city was built, and made the houses tremble, great and small. The tallest towers shook.

Then, with an indescribable din and a shaking that knocked Tab off her feet, the entire city of Quentaris, hills, harbour and all, wrenched free from the earth that had cradled it for over a thousand years, and rose shudderingly up into the sky, higher and higher, revolving faster and faster.

A party of adventurers led by the famous rift guide, Rad de La'rel, was just leaving a rift cave in the mountain range. They were galloping down the embankment as though Zolka had broken through the rifts. Then those in the vanguard toppled like bowled skittles. The ground shook like a blanket. Laden donkeys and horses whinnied, fear-crazed.

Tab held firmly onto the nearest parapet. The city trembled as it rose into the clouds with a tremendous roar of crushing rock and grinding chaos. There was a terrifying moment of blackness – then a sickening transition before blinding sunlight burst upon Quentaris. The city was still spinning, but slowly now… until it was sucked into the churning mouth of the vortex.

People stumbled about, dazed by what had befallen them. Unbelievably none of the city's buildings had collapsed – magic bonding had held them firm – but anything loose such as market tables and wagons had been smashed to kindling. One by one the survivors of this catastrophe realised that their entire city was now drifting like a sky pirate's ship over unfamiliar terrain.

It had been a year of enormous change.

Tab stood on the port-side battlements where she had stood exactly a year before, gazing out over the city. Bathed in brilliant sunlight, the waters of the now-enclosed harbour sparkling, Quentaris was a buzz of activity. It was market day down in the town. A forest of gaily coloured stalls and awnings, not to mention some large outlandish umbrellas, had blossomed in the city square, clustering about the base of the mainmast.

Overhead, vast canvas sails crackled and snapped in the wind. The spider web of rigging bounced. Tab craned her neck, staring up at the colossal world of rope and canvas, of bouncing catwalks, towers, turrets, and a complex bridge structure from which Quentaris was steered. Squinting against the sun's bril liance, Tab saw the tiny figures of riggers, canvassers, splicers, knot-men, dousers, lookouts, mizzen-men and the former roofies who made excellent sky sailors – not to mention officers and midshipmen – crawling and bobbing amidst the broad sheets of canvas.

Quentaris looked exactly like an enormous sailing ship, from the rift hills at the stern, to the jutting bowsprit of the prow, and various great masts in between. And, just like such a ship, Quentaris sailed.

Only it wasn't the sea that it sailed upon. It was the sky. Tab leaned out over the parapet and stared into… space. A cloud wafted past. She looked down as Quentaris cast its huge shadow over the alien terrain far below. A herd of galumphing, three-horned creatures stampeded. The fear-crazed animals left a trail of billowing reddish dust in their wake. Above, a flock of sharp-beaked birds with pink plumage flitted amidst the immense masts and rigging. The fore-topsail and main-topsail were fully bloated. Everyone had become accustomed to the ever-present raucous flapping of the city's sails. With a fresh breeze, Quentaris was travelling at a swift six knots.

Tab never tired of this sight.

She thought Quentaris, a city she had always loved, had become magnificent. Indeed, in some fashion that she couldn't quite put her finger on, Quentaris had come alive. The sails were its lungs, capturing great gasps of air to thrust it on its way; the rigging was its sinews, holding everything together; the masts, its bones; and the great slab of earthen rock upon which the city and harbour and surrounding wall sat, its flesh and organs. The sails crackled, the rigging sang, and the two great engine houses – port and starboard – throbbed rhythmically as they converted the magical energy of icefire into the ire ore that powered the gigantic propellers that were used when the winds died and the city becalmed.

Despite all this, Tab shivered as she remembered the Rupture itself, the wrenching upheaval that had thrown Quentaris into the rift vortex that had formed in the sky. Tab knew that Fontagu and the stolen icefire gem had been responsible. She even knew the name of the spell used, having returned to the slaughterhouse to find both the gemstone and the scrap of paper bearing the words Fontagu had muttered.

Only by then, all the words, except for the sealing phrase, were fading even as she stared at the note. Later she had looked up the remaining words in an ancient book of charms in the library of the Magicians’ Guild. Only one spell used such words.

The Spell of Undoing.

From the entry, she had come to understand that somehow Fontagu had messed up. The Spell of Undoing, used properly, should have ‘undone’ the city: undone its prosperity, its luck, its success in battle, as well as the workings of the rift caves. In the process, many might have died.

But it had somehow gone wrong, perhaps because of Fontagu's nervous mispronunciation of the final words.

Instead, it had ‘undone’ Quentaris in much the way that one popped a cork from a bottle and threw it away. Tab knew this wasn't a very ‘magical’ way of thinking, but it helped her make sense of what had happened.

Of course, no one knew of her involvement in the Rupture, nor of Fontagu's. She dreaded the day the citizens of Quentaris found out. Without a doubt they would hang Fontagu from the nearest spar. Tab, who had merely distracted Fontagu at the critical moment, might simply be thrown overboard or, if the citizens were feeling generous, keelhauled.

Quentaris had a very large keel.

On the other hand, there were a few who pointed out that the theft of the icefire had summoned a great many magicians back to Quentaris, in time to be marooned along with everyone else. And without the magicians, there would be no Navigators’ Guild; without the magicians, there would be no hope of finding their way home.

Without the magicians, Tab would also not have become an apprentice guildswoman, clerical division. Being a runner and a clerk was a long way from being a magician, but at least she got to loiter with magicians and, when she was lucky, to see magic at work in its various forms: Earth, Air, Fire and Water.

A sweeper came slowly towards her along the wall. His cap was pulled down over his face and he seemed intent on his work, though Tab saw that he handled his broom sloppily, almost with disdain – as if he thought himself meant for better things.

‘This is so demeaning,’ said Fontagu, looking up from his broom. He leaned on it, scowling at Tab's big grin. ‘And look what they make me wear. Grey. I ask you, how can you make a statement with grey?’ He brushed some grime from his tunic and sniffed.

‘Well,’ said Tab, ‘that's your lot for my keeping quiet about your causing this mess. I believe the Dung Brigaders still have vacancies, if you'd like to apply.’

Fontagu paled. ‘No, no, not at all! Look, see, see how much I love my work!’ He started sweeping vigorously but only managed to conjure up a dust cloud that sent them both into great splutters of coughing. Fontagu sighed gloomily. ‘I'm not really very good at this.’

‘I would never have noticed.’