“Yes . . . ” Hayden was thinking. “Yes, I see that now, of course. Stupid of me, really.” He rubbed a thumb experimentally along the point of his jaw. “I suppose it must have been around the third night when I just couldn’t bear it any longer . . . ”

Somewhere towards the witching hour, after the last of the cheap pills had worn off, he admitted to himself there was nothing for it but to seek help. He ought to have done it before, of course, but a quick status check had confirmed his worst fears: his bargain-basement traveller’s insurance didn’t cover emergency dental treatment. He’d have to pay for the treatment himself, and if the pricing policies of the first ten local dentists on the list he’d googled on his laptop were at all representative, even a quick backstreet extraction sans anaesthetic would leave a hole in his current account roughly the size of Hong Kong harbour. This trip was running on the very edge of profitability as it was: one thumping dental bill would leave him dangerously out of pocket.

Over and above that—go on, admit it—he just didn’t like dentists. They scared him: everything about them, their white coats, their whirring drills, the lights they shone in your eyes. Their cold unblinking stares, as they leaned over you and stuck sharp metal spikes into your soft pink gums. The way they charged you an arm and a leg for the privilege of inflicting their medically sanctioned torture. Dentists? Monsters. Who else would volunteer for a job like that? It was a measure of the extremity of Hayden’s predicament that he’d even considered going to one in the first place. Now, having come to the end of his tether, he was checking through the small-print of his freelance employment contract to see whether it might cover medical treatment. It didn’t, of course: Hayden could almost hear the sniggers of the sadists in the legal department as they carefully precluded even the possibility of such a claim. Smug toothy bastards. He stuffed the contract back in his briefcase, riffled through the rest of his papers—

—and came up with the Scientific American he’d bought for the flight. The magazine was folded open to the last article he’d been reading, back on the plane: “MIRACLE” CHINESE DENTAL TREATMENT TO UNDERGO TRIALS IN WEST. Squinting from the pain, he tried to focus on the headline; the final clause dissolved beneath his crosseyed scrutiny, leaving just four enormous words that filled the entire page, like newspaper declarations of war. “MIRACLE” CHINESE DENTAL . . . and as he stared, those super-cautious quotes, those weasel qualifiers, seemed to dwindle all the way into transparency and pop like tiny bubbles in champagne. A miracle; Christ, yes, that was what he wanted, a bucket of that, please.

The hotel porter, once buzzed up to the room and acquainted with the contents of Hayden’s wallet, was gratifyingly eager to help. Hayden handed him the copy of Scientific American: scanning through the article intently, he nodded from time to time, then looked up. “You want—drugs!” he announced brightly.

“No—well, sort of, yes—look, I want medicine.” Hayden pointed to the article, then to his swollen cheek. “Medicine. For toothache.”

“Medicine . . . ?” The porter (whose name was Jimmy Tsui) frowned. “You use up all your medicine already?” Only the night before, he’d pointed Hayden in the direction of the pharmacy round the corner.

“It’s not strong enough,” explained Hayden. “I need something much much stronger—do you understand?”

“Sooo . . . you want drugs?”

“Not just any drugs,” insisted Hayden. “This drug. I want to know where in Hong Kong I can go to get some of this—look, here, this miracle Chinese dental treatment, see?” Why was everything so complicated?

Between Hayden’s ravaged jaw and the magazine article, enlighten-ment gradually dawned on Jimmy Tsui. He jabbed a finger at the magazine and rattled off a musical burst of syllables. It might have been a brand name; it sounded pithy and to the point, uuan-shan-dhol. Hayden tried it out himself: “Wang-chang . . . wan-shang-dole? Is that this? The miracle thing?”

“Miracle, yes . . . ” The porter nodded hard, his eyes saucer-wide in the wonderment of understanding. “You want—ask man about this?” He indicated the article, its illustration of a human head scanned by MRI into skull-like abstraction, all fangs and empty eye sockets. “Man who will sell you medicine . . . for this?” He pointed gingerly at Hayden’s mouth.

“God, yes! Do you know anywhere I can get it? I can go up to five thousand Hong Kong, maybe seven . . . ”

At long last, the porter seemed to have grasped it. “I know good doctor, yes, he got—all what you want! My shift—over, fifteen minutes! We take taxi into Mong Kok, you and me!” He tapped a finger against his nose, then laughed a trifle nervously as Hayden followed suit. Almost weeping at the prospect of relief, Hayden made to shake his hand, but the porter was already excusing himself, slipping backwards through the door in a deferential bow.

And so, soon after midnight, Hayden found himself crossing the harbour in the company of Jimmy Tsui. The taxi injected them directly into the rush and clamour of the Mong Kok strip, close by Sim City and the soaring Grand Tower. Even at this hour the bright sidewalks were chock-full of pedestrians jammed shoulder-to-shoulder, streets glittering and congested like the chutes of the pachinko machines in the slot parlours, all played out to a chorus of tinny chipmusic leaking from headphones and shop doorways. Above their heads neon advertisements flickered the length of Shantung Street, pulsing through the pollution layer, making rainbows on the oily tarmac underfoot. The night smelled of spent fireworks and overheated motherboards.

Jimmy tugged at his sleeve, once, twice. “Not far now! Follow me!” Hayden did his best to keep up with the porter as he dodged and shouldercharged across the road. Once he caught sight of himself in an unlit window: the surgical face-mask with which Jimmy had thought-fully provided him—“Best you wear this—keep mouth hidden!”—made him look like the mad doctor in a Frankenstein movie. It was all in the eyes, he decided, before hastening on to follow Jimmy down a narrow entranceway between two buildings.

The walls on either side leaned in so close there was barely room for Hayden and Jimmy to walk line abreast. Optimistically, or else suicidally, a gang of kids came rollerblading at breakneck speed towards them: Hayden flattened himself against the graffitied concrete as they whizzed past, one hand raised to guard his face. Up ahead Jimmy had come to another right turn; he waited for Hayden to catch up before gesturing theatrically and exclaiming, “This Night-town! You in Night-town now!”

Night-town took the form of another, wider alley running parallel to the strip. Each of the commercial premises stripside seemed to have its corresponding—probably unlicensed—counterpart round the back: some were simple stalls of wood-strut and canvas, while others were breezeblock lean-tos built straight on to the backs of the buildings. Jury-rigged lighting run illegally off the mains lit up the bustling alley: between that and whatever moonlight could reach the concrete canyon, Hayden could just about pick his way through the detritus underfoot. Dismembered cardboard boxes blocked his way; drifts of Styrofoam packing beads, twisted snares of parcel strap, split plastic bags in the process of leaking their unguessable contents. Bedded down amongst the rubbish here and there were people lying slumped against the walls, needy or beyond need, it was impossible to tell. Whenever they passed one of these unfortunates, heads lolling anyhow, skins the colour and texture of mushrooms grown in tunnels, Jimmy would grab Hayden’s arm and hurry him onwards. All the while, the ambulant dwellers of Night-town padded past on their backstreet errands, clustering briefly by each chop stall before disappearing off into the shadows.

Extractor fans heaved and whirred stale second-hand odours at them: cigarette smoke, fast food, generator fumes. Hayden pulled his mask up over his nose and pressed on after Jimmy. Which of these booths was to be their destination? This one, perhaps: the concrete box with no door stacked floor to ceiling with cans of Kirin beer? Or the one opposite: racks of old iPods and Wiis, all scorched and heat-warped, the pinstriped proprietor perched toadlike on a tiny stool in the doorway, both hands permanently hidden inside the open briefcase that lay across his knees? Maybe this one: a whole wall full of Blu-ray discs, no cases, the discs hung up on nails, their laser-etched data tracks scattering rainbow moirés of light across the faces of the teenagers who examined them.

None of these, of course. Instead, Jimmy stopped outside a plain doorway towards the end of the block, in between a dirty-looking noodle parlour and a tattooist’s with screaming demon shingle. “This way,” he announced proudly, “the basement!” He ushered Hayden through the door, and followed after him down a flight of concrete stairs. At the first turn there lay sprawled another of the mushroom people. Hayden stepped gingerly over him, but Jimmy administered a sharp kick in the ribs that sent the man crashing against the wall. “Filthy monkey,” he spat after the unfortunate indigent as he scrambled away up the steps. He turned to Hayden. “You follow me,” he urged, and pushed past him down the stairway. By the light of red emergency bulbs, they continued their descent.