"You look like you've just been dug up."

That was the first thing she said when we met, and it was true enough. Her brother and I had driven four thousand miles in the last ten days, steadily heading north, and the last fifteen hours through fathoms of liquid mud, toppling rain and darkness. It was now just before midnight, a few miles short of the Ecuador border. My dress was stuck to me like skin. The red cotton one with a hundred-button front that I'd bought the week before in the north of Chile.

She could have been anywhere between forty and sixty-five, standing there in the insect-whirring light beneath the one lamppost in Suyo. We were standing in front of the bank, an adobe shack with a hand-painted sign saying 'BANCO PERUANO'. The letters crowded together toward the right hand end.

She was wearing fingerless gloves with webbing on the palms, the sort that golfers use and her smile was upside-down when we shook hands. I thought it might have meant distaste but later I saw it was just her smile, the way she did it. Her name was Eugenia.

With a wave of her hand into the dark she introduced the two men who were with her, Cirilio and Segundo. One was middle- aged and the other was younger and leaner and missing his two front teeth. They lived in Suyo during the rainy season, cropping sweetpith and working on the road when it got bad.

Cirilio's house was two doors up from where we had left the car and we all went there, walking up the muddy lane in the dark, while Eugenia introduced her brother to her friends. Segundo asked her in a soft and secret voice, "Y la Chinita?" She shrugged. Guzman told him my name was Shin-Ja, and that I was Korean, not Chinese. I was thinking, Who could possibly care? I've got the eyes, that's all that matters. Segundo gave me a very friendly smile then and shook my hand with both of his.

The house had three rooms and a bed in each. The walls were bare mud-brick and the roof was sheet-iron, noisy with the spank of beetles. We sat in the first room, Guzman, Segundo and I in a row on the bed, Eugenia on a stool by the table with its oil-lamp. Cirilio brought bowls of mazamorra, cracked corn in warm milk that he'd just taken from a cow.

"Did you bring any wine with you?" asked Eugenia to her brother.

We sat more comfortably when Cirilio brought two chairs, and we drank the bricks of wine Guzman brought from the floor of the car. The cardboard was warm and soft with wet but the seals were still intact. Cirilio didn't drink and Segundo took a thimbleful and declared that that was enough for him, smiling through the big gap in his mouth.

We got quickly drunk in the thick monsoon heat that pooled in the room, listening to the squall of insect life. It was a wild aggregate of shortwave that skirled and crackled and hissed in the eaves and beyond the door and down there in the corner by the bed. A tape of white noise played too slow, frequencies spreading out till the ceaseless morse of each message was audible. Insect radio, tuned to the marine band.

I'd started scratching, fast like a dog, and without thinking. Segundo disappeared and came back with two limes which he halved and gave to me. I licked one. He took it back, squeezed out some juice onto my wrist and rubbed my arms with the fruit, then my ankles and the back of my neck, speaking with a soft Welsh lisp, "Hlangre dulhle... lo' hlancudo' le' encanta la hlangre dulhle..." There was a sweet shine in his eyes.

"Sweet blood," translated Eugenia, "Zancudos like sweet blood." I asked her what they were. "Well mosquitoes have to land first before they can drink. Zancudos, they just fly in straight, like darts. The lime juice doesn't stop them but of course you should thank him for his help." She turned to the older man. "Cirilio, can we not get some coca here?"

Cirilio nodded and sent Segundo off. He was gone for ten minutes and came back with a polythene sack that held about three pounds of leaf. Eugenia made it her own, setting it next to her on the table. She took from one of her pockets a hard grey coil, like the furred element from an old kettle and broke a small lump from the end of it, wrapping it in a few of the leaves before tucking it away in her cheek.

"Lehir," she said when I asked her what it was. Then she took a leaf, nipped off the stalk, put the leaf in her mouth, took another, barely chewing at all, just a little sideways and lazily like a cow, nipped off the stalk, slipped the leaf in, and took another, "It's soda-ash. Go ahead." She broke off another piece and left it for me on the table, resuming the slow stoking of her cheek. I did as she had done and she warned me, "Wrap it up or it'll burn your mouth."

The leaves were half-dried and sharp like small bay-leaves and made an uncomfortable pricking in my mouth. But Guzman and I kept pace with his sister, adding leaves every so often, chaining them. Neither Segundo nor Cirilio bothered with the coca. They drank tea with slices of lime and one thing and another kept them smiling, as Eugenia told stories about herself, the while she packed her cheek with coca until it shone: Eugenia in Europe, Eugenia in the Middle East, Eugenia in India, Eugenia generally not being taken for a ride.

"Is that where you got the shirt?" I asked. "It looks like tusser."

"Oh yes," she sounded bored. "It's wild silk, it's called Ta-sar, of course it's oak-silk... it's very rough." By now she couldn't close her mouth properly and her words were wet.

"What, you got it in China?"

"No. In India."

"India. Well it won't be oak then, you know Indian tusser, I mean the moth, you see they eat Zizyphus. It's the jujube tree."

Eugenia put two fingers in her mouth and brought out the fat greenblack cud she'd been working on for forty minutes, dumped it in the ashtray where it steamed like a cake of horseshit.

"I have an idea," Eugenia said, "that fed on coca they would probably spin faster when they cocoon." She laughed grimly, "So you'd get an ultra-fine thread. And think of the value," the weird smile was on her face. "Coca-silk, it would be so fine, there'd be a fortune, the real El Dorado again." She was starting again on her cheek, feeding in the leaves one by one, "Forget eradication, there'd be new plantations all over." She looked up. "But the taste is bitter. They might not be persuaded, the worms."

I took the heavy wad out of my own cheek and my cheek was numb. The insect noise was louder but it was programmed now, data-sets in process, no menace in it. Guzman was sat against the wall. He looked from his sister to me before disgorging the sogged chaff into his palm, putting it with the other two pats like he was ending a round of bidding.

"She'll help you," he said, turning again to his sister, but nodding his head sideways at me. He scratched his scalp viciously, "She's published papers on the subject," and he took a new handful of coca from the bag.

"Oh yes?" she still sounded bored, "What subject?"

I wasn't directly sensible of the temperature in the room. But it had to be very hot, I could tell from the regular drops of sweat spider-running down my sides, from the shine on Guzman's face, from the handkerchief Cirilio was wiping round his neck. Only Guzman's sister didn't sweat. Her fifty-year- old skin was smoothly yellowed, with a few old bristles. A page of goat-skin.

"Hybridisation."

Eugenia clicked her tongue and started a small performance, hawking to clear her soft-palate, then maunging on her cheekful of leaf to express the extract into a noisy swallowing.

"Well I'm a chemist really," I went on, encouraged by her act of indifference, "but I did some work with a colleague a few years ago. Spare time work." When I glanced at her she raised her eyebrows. She knew I was lying. Then I remembered the windows of the cocoon-shed in Kwachon, south of Seoul, that Mr.Lee painted white when we hatched the first brood.

Eugenia was looking at me in a new narrow way. I knew before she spoke that she'd heard something ugly from Guzman. Something untrue.

"If you're uncomfortable then don't go on," she said in her new narrow voice.

The oil-lamp had burnt low and her shadow blustered big in the corner of the room like a night-tree. Cirilio was dozing and Segundo had disappeared. The two Guzmans watched me. They fed slowly from the sack of coca between them on the table. A plum-beetle bounced twice round the room, landed flap! next to the sack and Guzman walled it round with an upturned glass.

I had the feeling I was on rails, I was too fast. Guzman released the beetle from the glass, and flicked it so it bulleted into the far wall.

"You see, my son..."

Saying that word, it was like I'd caught the end of the true filament. I couldn't help then but be unwound. The truth reeled itself because I'd been softened by the rainy heat, like those helpless cocoons of silk bobbing in their water-kennel, just near boiling, "... you know he died in a river. In running water." I reached for more leaves from the sack and Guzman passed them to me. "You know, if it had been a pool, if it had only been still. I would have coped." There was no movement in the room. Only the oil creeping up the wick, burning shadows in the air. So I asked for a cigarette and lit it, sitting in the almost-dark on the bed.

"He was three years old and a month and a bit. I had a Wednesday off one week in summer and we took the train out to Topyong, east of Seoul. You walk into the mountains from there, a mile, two miles or so, up the river; well... it's a stream, it's a fat stream coming down over boulders, through the woods. And it was just so hot, like this. It was the end of the rainy season, the last week of August. It was a lovely day, just lovely. When there was a glade you looked up and the light was coming down, bounding down over the clouds like water. Then there's a flat stretch where the woods stay on the far side and it's good for a picnic because on this side there's a kind of grassy bank almost to where the water is.

"He ate half of a Kraft slice and went and sat down in a pool of spillover that was separate from the stream. It was only shallow, a couple of inches, and hot from the sun, that's what he said. He said 'It's hot!' and stood up and sat down and stood up and sat down, holding the slice of cheese over his head. I suppose so it wouldn't get wet. I was reading, flicking through a magazine and there was a spread about autumn clothes. It said white was going to be big that autumn, all the models were wearing white, the page was so bright in the sun I couldn't see if there were different shades or what. So I turned over and I could see it better in my shadow but I couldn't see any difference between the whites."

The Guzmans were quiet. I looked down and the cigarette that was in my hand had a two inch long ash on it. "I didn't used to smoke then," I said, "I only flicked through magazines." I watched as the ash broke off and fell on the mattress, into powder. Guzman passed me a tin can they were using as an ashtray and in the weak candlelight I became mesmerised by the picture on the side: a lion in a cloud of bees, and the English words: Out of the strong came forth sweetness. It was a picture of a dead lion.

"I don't know what he did. Why he wasn't there when I checked again. You know, ten, twenty seconds later and he wasn't there. The water was stronger than it looked lying down. And you know? he hadn't even gone so far. And I saw he'd cut his toe first of all. And that he was the wrong way up. But his legs were kicking... he was where the water went down between, these rocks into a lower pool. His arms were at his sides... he was, aiming at the pool below. And the water was so big, it was so heavy that it just had him - it was so steady. You couldn't see that it was fast, which it was, because... well he was stuck there he was jammed by his shoulders between the two rocks... under this... lens, of water moving over him. Well it was the water that was making his legs kick. Thinking about it... I don't think he was doing it. He wasn't alive then.

"I just couldn't bury him. But how could I. If it had been that pool of spillover, or a swimming pool, I know I could have. You could swap a water-grave for an earth-grave. But it was only as if he ...had stalled out there in the river.

"So it was right I should hold on. I only had his body and it wasn't as if he'd meant to leave. It was the way he was, that was gone; the sense he made of things was gone. I've no doubt it could have been found, with ...you know, if there were only the right equipment.

"I don't know if Mr.Lee really understood. Someone told me once he'd had a daughter who'd died but he never spoke about it. And it wasn't the point really. I was his boss and it was a government lab we were in. You can avoid questions. And he had his own reasons, his professional inquiry. Mr.Lee is very strait-laced, for a young man.

"He'd been at Hanil Research Labs since university. Hanil, the huge textile company. Of course there's still a big premium on natural silk, but you have to raise the mulberry for them, and it's too time-consuming for one thing. Mr.Lee had spent six years breeding silkworms, crossing, recrossing with other kinds of moth, looking for hybrids that'd make a profit. They've one in commercial use which feeds Ok on wool-waste, which is cheaper. But the silk is knotty and he says it doesn't reel very well. But some years before I met him he'd produced an odd one. A carrion moth he called it.

"There's this island in the East Sea, that's between Japan and Korea, and it's an old volcano, completely on its own a long way out and it's got some species you don't find on the mainland. And one of them is a sand-fly, Phlebotomus syrrhapti, and it's a deal bigger than most. There's one around the Mediterranean that carries dum-dum fever. But the thing is, a sand-fly isn't a fly at all. It's a biting moth, sanguivorous, you know feeds on blood? The Korean one, the syrrhapti, has a wing-span of about three centimetres, which is gross for a sand-fly. I suppose because it lives off cattle. So Mr.Lee crossed it with a wild silkmoth, Attacus cynthia, that feeds on ailanthus, the Tree of Heaven. Makes my heart race every time I think of that: silk from the Tree of Heaven. But he hadn't given the cross a new name. He just called it cynthia- A. I told him it sounded like my own name. Like Shin Ja. But he didn't really see the connection. It was just Latin to him.

"He still had about a half ounce of graine under nitrogen, in his collection. Enough for say ten, twenty thousand cocoons, about three kilos of reeled silk. But it had no commercial interest for him. Just an oddity.

"When once I'd thought of it, I never doubted again, that it was right. To make Tae Hyun's silk. I chose that. So don't think it was wrong. I chose, that I would dye his silk waterblue, and wear it always, as a river round me.

"It was already September. He'd been in the cold room at the hospital for six weeks, listed as a donor. And of course there would still be the cremation after it was over. So I paid money in a white envelope, to the attendant there, that he would fill out the form. I don't know what you'd call it, a ...post-mortem release form? Just for two weeks, for a second opinion.

"It doesn't take long. From seed to imago, the life-cycle is only a month. They stop feeding at the end of the third week and then they spin. It was the middle fortnight that I wanted. To spin Tae Hyun back again.

"So we raised a gramme on agar, and at the first moult we switched them to a protein film. Then the second moult was late, at about eight days, and they were getting too big. They were already at about two inches. They looked stretched. Mr.Lee was worried that they might get the grasserie if we left it any later. It's a sickness, makes their blood go milky and they swell up and they won't cocoon. He decided it had to be then.

"I know it's no different to what happens to us in the ground. Well is it really any different? Isn't it better? If nature ...can make something of the death. Some evocation, maybe, of the life. Shouldn't ...nature do that?

"And anyway it was all autumn for those two weeks. It really only lasted that fortnight, when the leaves turned paint red and yellow and the air was so fresh again, after the summer. The Olympic games were on in Seoul. I was calling Mr.Lee five times a day at the facility he used, to check they were healthy and growing well, and no sickness.

"It sounds strange now ...I'm not even sure I should say it. But, well I bought a white coat to celebrate, the day he reported the first few dozen were up on the mounting, and had started spinning. There was something in his voice. He was obviously pleased, professionally. He told me the filament was excellent, from the one he had examined; three to four microns thick, twice the Bombyx width, which makes the mulberry silk; and a striking deep green in colour he said. The colour of deep water. It would be you see, wouldn't it?

"And later, you know they reeled so beautifully. I remember it was the day after, you know, whoever it was won that race, the fastest ever hundred metres they said, when we sorted the cocoons. Six hundred and ninety-one in all. About a pound in weight, and that was quite heavy. But just one in your hand, it was weightless. And more blue than green. Dark as a damson, and about that size but weightless, with a greygreen bloom of floss rising off the surface. It was so compact. You wouldn't believe how tightly made and perfect. It kicked lightly in your hand, when the creature changing inside noticed the heat from your palm.

"We reeled the six hundred and incubated the rest to term. I wanted, sentimentally I suppose, to see them fly. It was greed, I realised, to want that too. Because they never did emerge. Though we watched them struggle hard enough, rocking backwards and forwards on the trays. About half managed to pierce the end of the puparium but the cocoon was too much for them. The special silk they'd made, it wouldn't let them out. Their own silk was too strong for them.

"It was clear to me then. That Tae Hyun really was dead. It hadn't been quite clear before, in my mind. That it really meant an end."

Guzman and his sister were just shadows by then, for the light that had burned so low was somehow now behind them. Eventually Eugenia asked what I had done with the silk.

In that sweltering heat my fingers felt cool. Cool and harmless. Methodically I undid the first fifty buttons on my dress, and I showed her.

"I'm sorry, but I don't believe you," was all she said.

I looked at her. It made me want to smile, feeling the warm run of silk beneath my fingers, stroking again Tae-hyun's warm back as he slept. The warmth of spring weather.

"Your nephew," I said. It was all I could think of to reply. I got off the bed, walked softly, three steps across the room, and took Eugenia's hand by the wrist. "You won't believe unless you touch," I told her, placing her palm on my stomach, feeling her fingers crawl to the side of my waist. She felt the quality, felt for her own flesh and blood between finger and thumb. Then I heard her swallow.

"Ok," she said, "so what if I believe you?"

And it made me feel like a curious kind of saviour when I saw that she was crying too. A run of fine, rational tears, tears full of salt thought. She had to lick them away from the corners of her mouth.