Magnus took a deep breath and opened it.

Magnus The answer must be no. I can tell you don't really mean it, so don't pretend you do.

Don't bother sending me any more e-mails, I won't reply to them.

C.

Magnus felt a rush of anger. She was right, of course, he didn't really want to marry her, and there was no chance that he would be able to persuade her that he did. But he was worried about her safety. He typed rapidly.

Hi Colby, I am very worried about you. I need to get you to safety. Now. If you don't want to come with me then I will try to arrange something else. So please get in touch with me, or if not me, with the FBI, or with Deputy Superintendent Williams at Schroeder Plaza. If you do contact him, speak to him directly and only him.

Please do this one thing for me, Love Magnus It probably wouldn't work, but it was worth a try.

Magnus spent the rest of the afternoon in the murky waters of the Internet, feeling his way around forums and chat rooms. There were an awful lot of Lord of the Rings fans out there. They seemed to split into the amateurs and the obsessives. The amateurs were mostly thirteen-year-old boys who couldn't spell and had seen the movies and thought the Balrogs were really cool. Or they were thirteen-year-old girls who couldn't spell and had seen the movies and thought that Orlando Bloom was really hot.

These brief posts were outweighed by mighty articles from the obsessives, who wrote thousands of words on obscure aspects of Middle Earth, Tolkien's invented world. There were disputes about whether those Balrogs had real wings or metaphysical ones, or about why there were no young ents, or about exactly who or what was Tom Bombadil.

Magnus hadn't read The Lord of the Rings since he was thirteen himself, and he had only a vague recollection of all these characters. But it wasn't just the obscurity of the arguments that surprised him, it was the passion and occasionally vitriol that accompanied them. To a great many people all over the world, The Lord of the Rings was clearly very, very important.

After two hours he found a posting from a man named Isildur. An obsessive. It consisted of several paragraphs commenting on a long academic article by someone called John Minshall on the nature of the power of the One Ring in The Lord of the Rings.

There are a number of rings of power in Tolkien's book, all made by elves, except for the greatest of them, the One Ring to rule them all, which was made by Sauron, the Dark Lord. Long before the events of the book took place a desperate battle was fought between the evil Sauron and an alliance of men and elves; a battle which was won by the alliance. The ring was cut off the Dark Lord's hand by a man named Isildur. But afterwards, on his march home, the victorious Isildur and his men were waylaid by orcs. As Isildur tried to escape he jumped into a river, where the ring slipped off his finger and was lost. Soon afterwards the orcs caught him and he was shot through with arrows.

The ring lay at the bottom of the river for centuries until it was discovered by a hobbit-like creature named Deagol who was fishing there with his friend Smeagol. Smeagol was overwhelmed with desire for the beautiful glittering ring, and when his friend refused to give it to him, he strangled him and put the ring on his own finger. Over time Smeagol was consumed by it, becoming a slithering, obsessive creature called Gollum, until eventually, centuries later, the ring was taken from him by Bilbo Baggins, the hero of Tolkien's first book, The Hobbit.

The ring has all kinds of powers. The keeper of the ring does not grow old, but eventually he becomes weary and fades away. If the holder wears the ring, he becomes invisible to normal mortals. Over time, the ring exerts a power over its keeper, causing him to lie, cheat or even kill to maintain possession of it. Wearing it becomes an addiction. But most importantly, Sauron, the Dark Lord, is searching for the ring. When he finds it he will gain total domination of Middle Earth. The only way the Ring can be destroyed is if it is taken to Mount Doom, a volcano in the centre of Mordor, Sauron's own country, and thrown into the 'Crack of Doom'. This becomes the quest for Bilbo's nephew, a hobbit named Frodo.

Minshall argued that the powers of the ring showed that Tolkien had been inspired by Wagner's Ring Cycle of operas, in which the gods compete to take control of the Ring and dominate the world.

This idea seriously upset the present-day Isildur.

He quoted Tolkien himself who denied that there was a connection, claiming that 'both rings are round, and there the resemblance ceases'. Then Isildur launched on a long discourse quoting from the Saga of the Volsungs and the Prose Edda, both written in Iceland in the thirteenth century. He claimed that Tolkien had read the Volsung Saga when he was still a schoolboy and that it had inspired him for the rest of his life.

Both these sources describe how three gods, Odin, Hoenir and the trickster god Loki, were travelling when they came upon a waterfall where a dwarf named Andvari was fishing in the shape of a pike. Loki caught him, and stole some gold from him. Andvari tried to keep back a magic ring, but Loki spotted it, and threatened to send the dwarf to Hel, who was Loki's daughter, the goddess of death, unless he gave the ring to Loki. Andvari laid a curse on the ring and disappeared into a rock. During the rest of the saga the ring passes from person to person, creating mayhem wherever it goes. Isildur seemed to believe that both J.R.R. Tolkien and Richard Wagner had read the Saga of the Volsungs, which explained the similarity between the two stories.

There followed a series of ever more heated postings back and forth, until a third commentator appeared calling Tolkien a liar and a plagiarist. This seemed to unite Minshall and Isildur in defence of their hero, and the subject was laid to rest there.

Magnus strongly suspected that this was the same Isildur who was Steve Jubb's partner: both of them shared an interest in the Volsung Saga. Fortunately the web page included a link to the e-mail address of the people posting the commentaries. Isildur's address indicated an Internet Service Provider from the US. The question was, how could Magnus find out who he was?

There was a small chance that sending him an e-mail asking him to help the Reykjavik police with a murder inquiry would elicit a response. There was a much greater chance that it would tip Isildur off that the police were on to him, and he would go quiet.

The previous year Magnus had been involved in the investigation of the rape and murder of a woman in the middle-class suburb of Brookline. She had received anonymous e-mails from a stalker. With the help of a young technician named Johnny Yeoh in Computer Forensics, Magnus had tracked down the IP address of the computer from which the e-mails had been sent, despite all kinds of ploys the sender had used to disguise it. It turned out he was the woman's next-door neighbour. He was now serving life in Cedar Junction.

Magnus had Isildur's e-mail address. All he needed to do was provoke an e-mail response from him, which would include a 'header' divulging the IP address of Isildur's computer.

He thought for a minute and then tapped something out.

Hi Isildur, I found your comment about the Saga of the Volsungs very interesting. Where can I get a copy?

Matt Johnson A simple, if slightly dumb question which would take Isildur only a few seconds to respond to, with luck not enough time to worry about the e-mail address from which it was sent. Worth a try.

The problem with e-mail correspondence was that you never knew how long a reply would take to arrive. It could be a minute, an hour, a day or a month. While he was waiting, Magnus checked how arni was doing. He had made some progress: he had found a lecturer in Linguistics at the University of New South Wales who claimed to be an expert on Tolkien's invented languages, of which there were supposed to be fourteen. Like Magnus, he had sent an e-mail inquiry and was waiting for a response.

arni had also found traces of an Isildur. There was someone using that nickname who seemed to be trying to build an online translation service into and out of Quenya, which was one of Tolkien's most detailed Elvish languages. Whether it was the same Isildur or some other Lord of the Rings obsessive using that name, they could not be certain.

Magnus went back to his own computer. He was in luck. There was a brief e-mail from Isildur.

Hi Matt You should be able to get a copy from Amazon. There is a good Penguin Classics edition. It's well worth reading. Enjoy.

Isildur Magnus hit a few keys on his computer, and a string of codes and numerals was revealed, the e-mail header.

Pay dirt.

'arni. Do you know anyone in your Computer Forensics department who could check out an e-mail header for me?'

arni looked doubtful. 'It's Saturday. They'll be at home. I could try to get hold of someone, but it will take a while. We might have to wait until Monday.'

Monday was no good. Magnus checked his watch. It was about lunch time in Boston. Johnny Yeoh was a civilian, not a police officer, but he was the kind of geek who would drop everything to be helpful if he was interested. Magnus and he had gotten on well, especially since Magnus had made sure that Johnny had received plenty of credit for his work in tracking down the Brookline killer. This would be just the kind of task to get Johnny's juices flowing.

Magnus tapped out a quick e-mail, cutting and pasting the header from Isildur's message. He made sure that there was nothing in the text of the e-mail that might suggest that he was anywhere but some city in the heart of America. He considered sending it to Johnny's Boston PD address via Agent Hendricks. The problem was Johnny wouldn't get it till Monday. Magnus needed a result more quickly than that.

Magnus could remember Johnny's home e-mail address he had used it enough times the previous year. He weighed the risks. There was no way that anyone would be monitoring Johnny Yeoh for a contact with Magnus. And although Lenahan had lots of buddies throughout the police department, Johnny was about the least likely person to be one of them.

He tapped out Johnny's address and pressed send.

With any luck, by morning they would know who Isildur was.

CHAPTER TEN.

THINGHOLT WAS A jumble of brightly coloured little houses in the central 101 postal district of Reykjavik, clinging to the side of the hill below the big church. It was where the artists lived, the designers, the writers, the poets, the actors, the cool and the fashionable.

It wasn't really a cop's neighbourhood, but Magnus liked it.

arni drove him along a quiet street just around the corner from the gallery Magnus had visited earlier that afternoon, and stopped outside a tiny house, probably the smallest in the road. The walls were cream concrete, and the roof lime-green corrugated metal, out from which jutted a lone window. Paint on walls and roof was peeling and the grass in the tiny yard at the side of the building was straggly and trampled down. Yet it reminded Magnus of the house he had grown up in as a child.

arni rang the doorbell. Waited. Rang the bell again. 'She's probably asleep.'

Magnus checked his watch. It was only seven o'clock. 'She's in bed early.'

'No, I mean she hasn't got up yet.'

Just then the door opened, and there stood a very tall, black-haired girl, with a pale face, wearing a skimpy T-shirt and shorts. 'arni!' she said. 'What are you doing waking me up at this hour?'

'What's wrong with this hour?' arni said. 'Can we come in?'

The woman nodded, a slow droop of her head, and stood back to let them in. They went through the hallway into a small living room, in which was a long blue sofa, a big TV, a couple of bean bags on the polished wooden floor and a bookcase heaving with books. The walls were panelled in wood; the longest had been painted in swirls of blue, green and yellow, giving an impression of a tropical island.

'This is my sister, Katrin,' arni said. 'This is Magnus. He's an American friend of mine. He was looking for a place to stay in Reykjavik and so I suggested here.'

Katrin rubbed her eyes and tried to focus on Magnus. Her top was more of a singlet than a T-shirt, one of her small breasts peeked out. She looked quite a lot like arni, tall, thin and dark, but where arni's features were weak, hers were strong, white face, angled cheekbones and jaw, thick short black hair, big dark eyes.

'Hi,' she said. 'How are you?' She spoke in English, with a British accent.

'I'm doing good,' Magnus replied. 'And you?'

'Yeah. Cool,' she mumbled.

'Shall we sit down and have a chat?' arni asked.

Katrin focused on Magnus, staring him up and down. 'No. He's cool. I'm going back to bed.' And with that she disappeared into a room off the hallway.

'Looks like you passed,' said arni. 'Let me show you the room.' He led Magnus up some narrow stairs. 'Our grandparents used to live here. It belongs to both of us now, and we rent out the room on the first floor. Here we are.'

They emerged into a small room with the basic furniture: bed, table, a couple of chairs and so on. There were two windows, pale evening light streamed in through one, and through the other Magnus could see the spire of the Hallgrimskirkja swooping high above the multicoloured patchwork of metal roofs. 'Nice view,' he said.

'Do you like the room?'

'What happened to the previous tenant?'

arni looked pained. 'We arrested him. Last week.'

'Ah. Narcotics?'

'Amphetamines. Small-time dealer.'

'I see.'

arni coughed. 'I would appreciate it if you could keep an eye on Katrin while you're here. In a low-key way, of course.'

'Will she mind that? I mean, is she happy sharing a place with a cop?'

'There's no need to tell her what you do, is there, do you think? And I wouldn't let Chief Superintendent Thorkell know you are staying here.'

'Uncle Thorkell wouldn't approve?'

'Let's just say that Katrin isn't his favourite niece.'

'How much is the rent?'

arni mentioned a figure that seemed very reasonable. 'It would have been twice that a year ago,' he assured Magnus.

'I believe you.' Magnus smiled. He liked the little room, he liked the tiny house, he liked the view, and he even liked the look of the weird sister. 'I'll take it.'

'Excellent,' said arni. 'Now let's go and get your stuff from your hotel.'

It didn't take long to ferry Magnus's bag back to the house, and once arni had made sure that Magnus was installed, he left him. There was no sound from Katrin.

Magnus stepped out on to the street. Consulting a city map, he walked one block down the hill and one block across. The sky had cleared, apart from a single thin slab that covered the top of the ridge of stone and snow that was Mount Esja. Magnus was beginning to spot a pattern: the base of the cloud moved up and down the mountain several times a day, depending on the weather. The air was clear and crisp. At eight-thirty it was still light.

He found the street he was looking for and made his way slowly along, examining each house as he went. Perhaps he wouldn't recognize it after all these years. Perhaps they had changed the colour of the roof. But as he followed the road over a hump he saw it: the small house with the bright blue roof of his childhood.

He stopped outside it and stared. The old whitebeam was still there, but a rope had been added to one of the branches. A good idea. A deflated football lay in a bed of daffodils, just about to bloom. He was glad there were still children there; he guessed most of the houses in that neighbourhood were now inhabited by young couples. A large Mercedes SUV stood proudly outside, containing two child seats. A far cry from his father's old VW Beetle.

He closed his eyes. Above the murmur of the traffic he could hear his mother calling oli and him inside for bed. He smiled.

Then the front door began to open and he turned away, embarrassed that the current owners would see a strange man leering at their house.

He made his way down the hill towards the centre of town. He passed a group of four men and a woman unloading equipment from a van. A band getting ready for Saturday night. The girl with the leopard-skin miniskirt and tail zipped past on her bicycle. In Reykjavik, he realized, you could expect to see the same person on the streets several times in one day.

He stopped at Eymundsson's bookstore, an all-glass jewel on Austurstraeti, where he picked up the last English copy of The Lord of the Rings, and a copy of the Saga of the Volsungs, in Icelandic.

He headed over towards the Old Harbour and another memory from his childhood, a small red kiosk, Baejarins beztu pylsur. He and his father used to go there every Wednesday night, after hand-ball practice, for a hot dog. He joined the line. Unlike the rest of Reykjavik, Baejarins beztu hadn't changed over the years, except there was now a picture outside of a grinning Bill Clinton tucking into a large sausage.

Munching his hot dog, he strolled through the harbour area and along the pier. It was a working harbour, but at this time of the evening it was peaceful. On one side were trawlers, on the other, sleek whale-watching vessels and small inshore fishing boats. There was a smell of fish and of diesel, although Magnus passed a squat white hydrogen fuel pump. He paused at the end, a respectful distance from a fisherman fiddling with his bait in a bag, and surveyed the stillness.

Beyond the harbour wall, the black rock and white snow of Mount Esja was reflected in the steel-grey water. A seagull wheeled around him, looking for a discarded morsel, but after a few seconds abandoned him with a disappointed cry. An officious looking motor boat cut through the harbour entrance on some mission of nautical bureaucracy.

Iceland had changed so much since the disruptions of his childhood, but what he recognized of Reykjavik brought back the early years, the happy years. There was no reason to visit his mother's family; they need never even find out he was in the country. He was pleased with the way his Icelandic seemed to be coming back so well, although he was aware that he spoke with a touch of an American accent: he needed to work on rolling those 'r's.

Reykjavik was a long way from Boston, a long way north of Boston. Twenty-five degrees of latitude. It wasn't just the cold air or the patches of snow that told him this Boston Harbor could be cold and bleak enough it was the light: clear but soft, pale, thin. There was a subtle warmth to the greys of the harbour in Reykjavik, compared with its harsher Boston counterpart.

But he would be glad when the trial date came up and he could go back. Although the Agnar case was an interesting one, he missed the violent edge of the streets of Boston. At some point over the last ten years, sorting out the day-to-day procession of shootings, stabbings and rapes, finding the bad guys and bringing them to justice, had become more than a job. It had become a need, a habit, a drug.

Reykjavik just wasn't the same. Toytown.

He felt a pang of guilt. Here he was safe, thousands of miles from that teeming city of drug gangs and police-corruption trials. But Colby wasn't. How could he get her to listen to him? He had the feeling the harder he pushed it, the more obstinate she would become. But why? Why did she have to be like that? Why did she have to use this issue, of all issues, to try to resolve the question of their relationship? If he were more emotionally subtle, if he were Colby herself, for example, he would be able to figure out a way of manipulating her to come with him. But as he tried to think of a plan, his head began to spin.

He sighed and turned back to the city. As he walked back up the hill along Laugavegur he looked out for a likely bar for a quick beer. Down a side street he spied a place called Grand Rokk. From the outside it looked a bit like a scruffy Boston pub, but with a tent covering tables at which a dozen people were smoking as they drank. Inside, the place was about a quarter full. Magnus eased his way past a group of regulars lined up along the bar and ordered himself a large Thule from the shaven-headed barman. He found a stool in the corner and sipped his beer.

The other drinkers looked as if they had been there a while. Quite a few had shot glasses containing a brown liquid crouching next to their beers. A line of tables along one wall were inlaid with the squares of chessboards. There was a game in progress. Magnus watched idly. The players weren't that good, he could beat them easily.

He smiled when he remembered challenging his father, a for-midable player, night after night. The only way Magnus could ever beat the clever strategist was by aggressive assaults on his king. They nearly always failed, but sometimes, just sometimes he would break through and win the game, to the pleasure of both father and son. Magnus knew that although his father would never dream of giving him a break, he was rooting for Magnus, always rooting for Magnus.

Too often, Magnus saw his father only through the dreadful prism of his murder, and forgot the simpler times before his death. Simpler, but not simple.

Ragnar was a very clever man, a mathematician with an international reputation, which was why he had been offered the position at MIT. He was also humane, the saviour who had whisked Magnus and his little brother away from misery in Iceland when they had feared that he had abandoned them. Magnus had many fond memories of his father from his teenage years: not only playing chess and reading the sagas together, but also hiking in the Adirondacks and in Iceland, and long discussions through the evening about anything that Magnus was interested in sparring matches in which his father always listened to Magnus and respected his opinion, yet also tried to prove him wrong.

But there was one aspect of his father's life that Magnus had never understood: his relations with women. He didn't understand why Ragnar had married his mother, or why he left her. He certainly didn't understand why he had then gone on to marry that awful woman Kathleen. She was the young wife of one of the other professors at MIT, and Magnus realized later that they must have been having an affair even when Magnus joined his father in Boston. Although outwardly charming and beautiful, Kathleen was a controlling woman who resented Magnus and Ollie. Within a few months of their marriage she seemed to resent Ragnar too. Why his father hadn't seen that coming, Magnus had no idea.

Eighteen months after that dreadful occasion, Ragnar was dead, found stabbed on the floor of the living room at the house they were renting for the summer in Duxbury, on Boston's South Shore.