On the last day of May 1941, a strange vehicle was seen on the streets of Morlunde, a city on the west coast of Denmark.

It was a Danish-made Nimbus motorcycle with a sidecar. That in itself was an unusual sight, because there was no petrol for anyone except doctors and the police and, of course, the German troops occupying the country. But this Nimbus had been modified. The four-cylinder petrol engine had been replaced by a steam engine taken from a scrapped river launch. The seat had been removed from the sidecar to make room for a boiler, firebox, and chimney stack. The substitute engine was low in power, and the bike had a top speed of about twenty-two miles per hour. Instead of the customary roar of a motorcycle exhaust, there was only the gentle hiss of steam. The eerie quiet and the slow pace gave the vehicle a stately air.

In the saddle was Harald Olufsen, a tall youth of eighteen, with clear skin and fair hair brushed back from a high forehead. He looked like a Viking in a school blazer. He had saved for a year to buy the Nimbus, which had cost him six hundred crowns - then, the day after he got it, the Germans had imposed the petrol restrictions.

Harald had been furious. What right did they have? But he had been brought up to act rather than complain.

It had taken him another year to modify the bike, working on school holidays, fitting it in with revision for his university entrance exams. Today, home from his boarding school for the Whitsun break, he had spent the morning memorizing physics equations and the afternoon attaching a sprocket from a rusted lawn mower to the back wheel. Now, with the motorcycle working perfectly, he was heading for a bar where he hoped to hear some jazz and perhaps even meet some girls.

He loved jazz. After physics, it was the most interesting thing that had ever happened to him. The American musicians were the best, of course, but even their Danish imitators were worth listening to. You could sometimes hear good jazz in Morlunde, perhaps because it was an international port, visited by sailors from all over the world.

But when Harald drove up outside the Club Hot, in the heart of the dockside district, its door was closed and its windows shuttered.

He was mystified. It was eight o'clock on a Saturday evening, and this was one of the most popular spots in town. It should be swinging.

As he sat staring at the silent building, a passer-by stopped and looked at his vehicle. "What's that contraption?"

"A Nimbus with a steam engine. Do you know anything about this club?"

"I own it. What does the bike use for fuel?"

"Anything that burns. I use peat." He pointed to the pile in the back of the sidecar.

"Peat?" The man laughed.

"Why are the doors shut?"

"The Nazis closed me down."

Harald was dismayed. "Why?"

"Employing Negro musicians."

Harald had never seen a colored musician in the flesh, but he knew from records that they were the best. "The Nazis are ignorant swine," he said angrily. His evening had been ruined.

The club owner looked up and down the street to make sure no one had heard. The occupying power ruled Denmark with a light hand, but all the same, few people openly insulted the Nazis. However, there was no one else in sight. He returned his gaze to the motorcycle. "Does it work?"

"Of course it does."

"Who converted it for you?"

"I did it myself."

The man's amusement was turning to admiration. "That's pretty clever."

"Thank you." Harald opened the tap that admitted steam into the engine. "I'm sorry about your club."

"I'm hoping they'll let me open again in a few weeks. But I'll have to promise to employ white musicians."

"Jazz without Negroes?" Harald shook his head in disgust. "It's like banning French cooks from restaurants." He took his foot off the brake and the bike moved slowly away.

He thought of heading for the town center, to see if there was anyone he knew in the cafes and bars around the square, but he felt so disappointed about the jazz club that he decided it would be depressing to hang around. Harald steered for the harbor.

His father was pastor of the church on Sande, a small island a couple of miles offshore. The little ferry that shuttled to and from the island was in dock, and he drove straight on. It was crowded with people, most of whom he knew. There was a merry gang of fishermen who had been to a football match and had a few drinks afterward; two well-off women in hats and gloves with a pony and trap and a stack of shopping; and a family of five who had been visiting relations in town. A well-dressed couple he did not recognize were probably going to dine at the island's hotel, which had a high-class restaurant. His motorcycle attracted everyone's interest, and he had to explain the steam engine again.

At the last minute a German-built Ford sedan drove on. Harald knew the car: it belonged to Axel Flemming, owner of the island's hotel. The Flemmings were hostile to Harald's family. Axel Flemming felt he was the natural leader of the island community, a role which Pastor Olufsen believed to be his own, and the friction between the rival patriarchs affected all other family members. Harald wondered how Flemming had managed to get petrol for his car. He supposed anything was possible to the rich.

The sea was choppy and there were dark clouds in the western sky. A storm was coming in, but the fishermen said they would be home before it arrived, just. Harald took out a newspaper he had picked up in the town. Entitled Reality, it was an illegal publication, printed in defiance of the occupying power and given away free. The Danish police had not attempted to suppress it and the Germans seemed to regard it as beneath contempt. In Copenhagen, people read it openly on trains and streetcars. Here people were more discreet, and Harald folded it to hide the masthead while he read a report about the shortage of butter. Denmark produced millions of pounds of butter every year, but almost all of it was now sent to Germany, and Danes had trouble getting any. It was the kind of story that never appeared in the censored legitimate press.

The familiar flat shape of the island came closer. It was twelve miles long and a mile wide, with a village at each end. The fishermen's cottages, and the church with its parsonage, constituted the older village at the south end. Also at the south end, a school of navigation, long disused, had been taken over by the Germans and turned into a military base. The hotel and the larger homes were at the north end. In between, the island was mostly sand dunes and scrub with a few trees and no hills, but all along the seaward side was a magnificent ten-mile beach.

Harald felt a few drops of rain as the ferry approached its dock at the north end of the island. The hotel's horse-drawn taxi was waiting for the well-dressed couple. The fishermen were met by the wife of one of them driving a horse and cart. Harald decided to cross the island and drive home along the beach, which had hard-packed sand - in fact it had been used for speed trials of racing cars.

He was halfway from the dock to the hotel when he ran out of steam.

He was using the bike's petrol tank as a water reserve, and he realized now that it was not big enough. He would have to get a five-gallon oil drum and put it in the sidecar. Meanwhile, he needed water to get him home.

There was only one house within sight, and unfortunately it was Axel Flemming's. Despite their rivalry, the Olufsens and the Flemmings were on speaking terms: all members of the Flemming family came to church every Sunday and sat together at the front. Indeed, Axel was a deacon. All the same, Harald did not relish the thought of asking the antagonistic Flemmings for help. He considered walking a quarter of a mile to the next nearest house, then decided that would be foolish. With a sigh, he set off up the long drive.

Rather than knock at the front door, he went around the side of the house to the stables. He was pleased to see a manservant putting the Ford in the garage. "Hello, Gunnar," said Harald. "Can I have some water?"

The man was friendly. "Help yourself," he said. "There's a tap in the yard."

Harald found a bucket beside the tap and filled it. He went back to the road and poured the water into the tank. It looked as if he might manage to avoid meeting any of the family. But when he returned the bucket to the yard, Peter Flemming was there.

A tall, haughty man of thirty in a well-cut suit of oatmeal tweed, Peter was Axel's son. Before the quarrel between the families, he had been best friends with Harald's brother Arne, and in their teens they had been known as ladykillers, Arne seducing girls with his wicked charm and Peter by his cool sophistication. Peter now lived in Copenhagen but had come home for the holiday weekend, Harald assumed.

Peter was reading Reality. He looked up from the paper to see Harald. "What are you doing here?" he said.

"Hello, Peter, I came to get some water."

"I suppose this rag is yours?"

Harald touched his pocket and realized with consternation that the newspaper must have fallen out when he reached down for the bucket.

Peter saw the movement and understood its meaning. "Obviously it is," he said. "Are you aware that you could go to jail just for having it in your possession?"

The talk of jail was not an empty threat: Peter was a police detective. Harald said, "Everyone reads it in the city." He made himself sound defiant, but in fact he was a little scared: Peter was mean enough to arrest him.

"This is not Copenhagen," Peter intoned solemnly.

Harald knew that Peter would love the chance to disgrace an Olufsen. Yet he was hesitating. Harald thought he knew why. "You'll look a fool if you arrest a schoolboy on Sande for doing something half the population does openly. Especially when everyone finds out you've got a grudge against my father."

Peter was visibly torn between the desire to humiliate Harald and the fear of being laughed at. "No one is entitled to break the law," he said.

"Whose law - ours, or the Germans'?"

"The law is the law."

Harald felt more confident. Peter would not be arguing so defensively if he intended to make an arrest. "You only say that because your father makes so much money giving Nazis a good time at his hotel."

That hit home. The hotel was popular with German officers, who had more to spend than the Danes. Peter flushed with anger. "While your father gives inflammatory sermons," he retorted. It was true: the pastor had preached against the Nazis, his theme being "Jesus was a Jew." Peter continued, "Does he realize how much trouble will be caused if he stirs people up?"

"I'm sure he does. The founder of the Christian religion was something of a troublemaker himself."

"Don't talk to me about religion. I have to keep order down here on earth."

"To hell with order, we've been invaded!" Harald's frustration over his blighted evening out boiled over. "What right have the Nazis got to tell us what to do? We should kick the whole evil pack of them out of our country!"

"You mustn't hate the Germans, they're our friends," Peter said with an air of pious self-righteousness that maddened Harald.

"I don't hate Germans, you damn fool, I've got German cousins." The pastor's sister had married a successful young Hamburg dentist who came to Sande on holiday, back in the twenties. Their daughter Monika was the first girl Harald had kissed. "They've suffered more from the Nazis than we have," Harald added. Uncle Joachim was Jewish and, although he was a baptized Christian and an elder of his church, the Nazis had ruled that he could only treat Jews, thereby ruining his practice. A year ago he had been arrested on suspicion of hoarding gold and sent to a special kind of prison, called a Konzentrazionslager, in the small Bavarian town of Dachau.

"People bring trouble on themselves," Peter said with a worldly-wise air. "Your father should never have allowed his sister to marry a Jew." He threw the newspaper to the ground and walked away.

At first Harald was too taken aback to reply. He bent and picked up the newspaper. Then he said to Peter's retreating back, "You're starting to sound like a Nazi yourself."

Ignoring him, Peter went in by a kitchen entrance and slammed the door.

Harald felt he had lost the argument, which was infuriating, because he knew that what Peter had said was outrageous.

It started to rain heavily as he headed back toward the road. When he returned to his bike, he found that the fire under the boiler had gone out.

He tried to relight it. He crumpled up his copy of Reality for kindling, and he had a box of good-quality wood matches in his pocket, but he had not brought with him the bellows he had used to start the fire earlier in the day. After twenty frustrating minutes bent over the firebox in the rain, he gave up. He would have to walk home.

He turned up the collar of his blazer.

He pushed the bike half a mile to the hotel and left it in the small car park, then set off along the beach. At this time of year, three weeks from the summer solstice, the Scandinavian evenings lasted until eleven o'clock; but tonight clouds darkened the sky and the pouring rain further restricted visibility. Harald followed the edge of dunes, finding his way by the feel of the ground underfoot and the sound of the sea in his right ear. Before long, his clothes were so soaked that he could have swum home without getting any wetter.

He was a strong young man, and as fit as a greyhound, but two hours later he was tired, cold, and miserable when he came up against the fence around the new German base and realized he would have to walk two miles around it in order to reach his home a few hundred yards away.

If the tide had been out, he would have continued along the beach for, although that stretch of sand was officially off limits, the guards would not have been able to see him in this weather. However, the tide was in, and the fence reached into the water. It crossed his mind to swim the last stretch, but he dismissed the idea immediately. Like everyone in this fishing community, Harald had a wary respect for the sea, and it would be dangerous to swim at night in this weather when he was already exhausted.

But he could climb the fence.

The rain had eased, and a quarter moon showed fitfully through racing clouds, intermittently shedding an uncertain light over the drenched landscape. Harald could see the chicken-wire fence six feet high with two strands of barbed wire at the top, formidable enough but no great obstacle to a determined person in good physical shape. Fifty yards inland, it passed through a copse of scrubby trees and bushes that hid it from view. That would be the place to get over.

He knew what lay beyond the fence. Last summer he had worked as a laborer on the building site. At that time, he had not known it was destined to be a military base. The builders, a Copenhagen firm, had told everyone it was to be a new coastguard station. They might have had trouble recruiting staff if they had told the truth - Harald for one would not knowingly have worked for the Nazis. Then, when the buildings were up and the fence had been completed, all the Danes had been sent away, and Germans had been brought in to install the equipment. But Harald knew the layout. The disused navigation school had been refurbished, and two new buildings put up either side of it. All the buildings were set back from the beach, so he could cross the base without going near them. In addition, much of the ground at this end of the site was covered with low bushes that would help conceal him. He would just have to keep an eye out for patrolling guards.

He found his way to the copse, climbed the fence, eased himself gingerly over the barbed wire at the top, and jumped down the other side, landing softly on the wet dunes. He looked around, peering through the gloom, seeing only the vague shapes of trees. The buildings were out of sight, but he could hear distant music and an occasional shout of laughter. It was Saturday night: perhaps the soldiers were having a few beers while their officers dined at Axel Flemming's hotel.

He headed across the base, moving as fast as he dared in the shifting moonlight, staying close to bushes when he could, orienting himself by the waves on his right and the faint music to the left. He passed a tall structure and recognized it, in the dimness, as a searchlight tower. The whole area could be lit up in an emergency, but otherwise the base was blacked out.

A sudden burst of sound to his left startled him, and he crouched down, his heart beating faster. He looked over toward the buildings. A door stood open, spilling light. As he watched, a soldier came out and ran across the compound; then another door opened in a different building, and the soldier ran in.

Harald's heartbeat eased.

He passed through a stand of conifers and went down into a dip. As he came to the bottom of the declivity, he saw a structure of some kind looming up in the murk. He could not make it out clearly, but he did not recall anything being built in this location. Coming closer, he saw a curved concrete wall about as high as his head. Above the wall something moved, and he heard a low hum, like an electric motor.

This must have been erected by the Germans after the local workers had been laid off. He wondered why he had never seen the structure from outside the fence, then realized that the trees and the dip in the ground would hide it from most viewpoints, except perhaps the beach - which was out of bounds where it passed the base.

When he looked up and tried to make out the details, rain drove into his face, stinging his eyes. But he was too curious to pass by. The moon shone bright for a moment. Squinting, he looked again. Above the circular wall he made out a grid of metal or wire like an oversize mattress, twelve feet on a side. The whole contraption was rotating like a merry-go-round, completing a revolution every few seconds.

Harald was fascinated. It was a machine of a kind he had never seen before, and the engineer in him was spellbound. What did it do? Why did it revolve? The sound told him little - that was just the motor that turned the thing. He felt sure it was not a gun, at least not the conventional kind, for there was no barrel. His best guess was that it was something to do with radio.

Nearby, someone coughed.

Harald reacted instinctively. He jumped, got his arms over the edge of the wall, and hauled himself up. He lay for a second on the narrow top, feeling dangerously conspicuous, then eased himself down on the inside. He worried that his feet might encounter moving machinery, but he felt almost sure there would be a walkway around the mechanism to allow engineers to service it, and after a tense moment he touched a concrete floor. The hum was louder, and he could smell engine oil. On his tongue was the peculiar taste of static electricity.

Who had coughed? He presumed a sentry was passing by. The man's footsteps must have been lost in the wind and rain. Fortunately, the same noises had muffled the sound Harald made scrambling over the wall. But had the sentry seen him?

He flattened himself against the curved inside of the wall, breathing hard, waiting for the beam of a powerful flashlight to betray him. He wondered what would happen if he were caught. The Germans were amiable, out here in the countryside: most of them did not strut around like conquerors, but seemed almost embarrassed at being in charge. They would probably hand him over to the Danish police. He was not sure what line the cops would take. If Peter Flemming were part of the local force, he would make sure Harald suffered as much as possible; but he was based in Copenhagen, fortunately. What Harald dreaded, more than any official punishment, was his father's anger. He could already hear the pastor's sarcastic interrogation: "You climbed the fence? And entered the secret military compound? At night? And used it as a shortcut home? Because it was raining?"

But no light shone on Harald. He waited, and stared at the dark bulk of the apparatus in front of him. He thought he could see heavy cables coming from the lower edge of the grid and disappearing into the gloom on the far side of the pit. This had to be a means of sending radio signals, or receiving them, he thought.

When a few slow minutes had passed, he felt sure the guard had moved on. He clambered to the top of the wall and tried to see through the rain. On either side of the structure he could make out two smaller dark shapes, but they were static, and he decided they must be part of the machinery. No sentry was visible. He slid down the outside of the wall and set off once again across the dunes.

In a dark moment, when the moon was behind a thick cloud, he walked smack into a wooden wall. Shocked and momentarily scared, he let out a muffled curse. A second later he realized he had run into an old boathouse that had been used by the navigation school. It was derelict, and the Germans had not repaired it, apparently having no use for it. He stood still for a moment, listening, but all he could hear was his heart pounding. He walked on.

He reached the far fence without further incident. He scrambled over and headed for his home.

He came first to the church. Light glowed from the long row of small, square windows in its seaward wall. Surprised that anyone should be in the building at this hour on a Saturday night, he looked inside.

The church was long and low-roofed. On special occasions it could hold the island's resident population of four hundred, but only just. Rows of seats faced a wooden lectern. There was no altar. The walls were bare except for some framed texts.

Danes were undogmatic about religion, and most of the nation subscribed to Evangelical Lutheranism. However, the fishing folk of Sande had been converted, a hundred years ago, to a harsher creed. For the last thirty years Harald's father had kept their faith alight, setting an example of uncompromising puritanism in his own life, stiffening the resolve of his congregation in weekly brimstone sermons, and confronting backsliders personally with the irresistible holiness of his blue-eyed gaze. Despite the example of this blazing conviction, his son was not a believer. Harald went to services whenever he was at home, not wanting to hurt his father's feelings, but in his heart he dissented. He had not yet made up his mind about religion in general, but he knew he did not believe in a god of petty rules and vengeful punishments.

As he looked through the window he heard music. His brother Arne was at the piano, playing a jazz tune with a delicate touch. Harald smiled with pleasure. Arne had come home for the holiday. He was amusing and sophisticated, and he would enliven the long weekend at the parsonage.

Harald walked to the entrance and stepped inside. Without looking around, Arne changed the music seamlessly to a hymn tune. Harald grinned. Arne had heard the door open and thought their father might be coming in. The pastor disapproved of jazz and certainly would not permit it to be played in his church. "It's only me," Harald said.

Arne turned around. He was wearing his brown army uniform. Ten years older than Harald, he was a flying instructor with the Army Aviation Troops, based at the flying school near Copenhagen. The Germans had halted all Danish military activity, and the aircraft were grounded most of the time, but the instructors were allowed to give lessons in gliders.

"Seeing you out of the corner of my eye, I thought you were the old man." Arne looked Harald up and down fondly. "You look more and more like him."

"Does that mean I'll go bald?"

"Probably."

"And you?"

"I don't think so. I take after Mother."

It was true. Arne had their mother's thick dark hair and hazel eyes. Harald was fair, like their father, and had also inherited the penetrating blue-eyed stare with which the pastor intimidated his flock. Both Harald and their father were formidably tall, making Arne seem short at an inch under six feet.

"I've got something to play you," Harald said. Arne got off the stool and Harald sat at the piano. "I learned this from a record someone brought to school. You know Mads Kirke?"

"Cousin of my colleague Poul."

"Right. He discovered this American pianist called Clarence Pine Top Smith." Harald hesitated. "What's the old man doing at this moment?"

"Writing tomorrow's sermon."

"Good." The piano could not be heard from the parsonage, fifty yards away, and it was unlikely that the pastor would interrupt his preparation to take an idle stroll across to the church, especially in this weather. Harald began to play "Pine Top's Boogie-Woogie," and the room filled with the sexy harmonies of the American South. He was an enthusiastic pianist, though his mother said he had a heavy hand. He could not sit still to play, so he stood up, kicking the stool back, knocking it over, and played standing, bending his long frame over the keyboard. He made more mistakes this way, but they did not seem to matter as long as he kept up the compulsive rhythm. He banged out the last chord and said in English, "That's what I'm talkin' about!" just as Pine Top did on the record.

Arne laughed. "Not bad!"

"You should hear the original."

"Come and stand in the porch. I want to smoke."

Harald stood up. "The old man won't like that."

"I'm twenty-eight," Arne said. "I'm too old to be told what to do by my father."

"I agree - but does he?"

"Are you afraid of him?"

"Of course. So is Mother, and just about every other person on this island - even you."

Arne grinned. "All right, maybe just a little bit."

They stood outside the church door, sheltered from the rain by a little porch. On the far side of a patch of sandy ground they could see the dark shape of the parsonage. Light shone through the diamond-shaped window set into the kitchen door. Arne took out his cigarettes.

"Have you heard from Hermia?" Harald asked him. Arne was engaged to an English girl whom he had not seen for more than a year, since the Germans had occupied Denmark.

Arne shook his head. "I tried to write to her. I found an address for the British Consulate in Gothenburg." Danes were allowed to send letters to Sweden, which was neutral. "I addressed it to her at that house, not mentioning the consulate on the envelope. I thought I'd been quite clever, but the censors aren't so easily fooled. My commanding officer brought the letter back to me and said that if I ever tried anything like that again I'd be court-martialed."

Harald liked Hermia. Some of Arne's girlfriends had been, well, dumb blondes, but Hermia had brains and guts. She was a little scary on first acquaintance, with her dramatic dark looks and her direct manner of speech; but she had endeared herself to Harald by treating him like a man, not just someone's kid brother. And she was sensationally voluptuous in a swimsuit. "Do you still want to marry her?"

"God, yes - if she's alive. She might have been killed by a bomb in London."

"It must be hard, not knowing."

Arne nodded, then said, "How about you? Any action?"

Harald shrugged. "Girls my age aren't interested in schoolboys." He said it lightly, but he was hiding real resentment. He had suffered a couple of wounding rejections.

"I suppose they want to date a guy who can spend some money on them."

"Exactly. And younger girls . . . I met a girl at Easter, Birgit Claussen."

"Claussen? The boatbuilding family in Morlunde?"

"Yes. She's pretty, but she's only sixteen, and she was so boring to talk to."

"It's just as well. The family are Catholics. The old man wouldn't approve."

"I know." Harald frowned. "He's strange, though. At Easter he preached about tolerance."

"He's about as tolerant as Vlad the Impaler." Arne threw away the stub of his cigarette. "Let's go and talk to the old tyrant."

"Before we go in . . ."

"What?"

"How are things in the army?"

"Grim. We can't defend our country, and most of the time I'm not allowed to fly."

"How long can this go on?"

"Who knows? Maybe forever. The Nazis have won everything. There's no opposition left but the British, and they're hanging on by a thread."

Harald lowered his voice, although there was no one to listen. "Surely someone in Copenhagen must be starting a Resistance movement?"

Arne shrugged. "If they were, and I knew about it, I couldn't tell you, could I?" Then, before Harald could say more, Arne dashed through the rain toward the light shining from the kitchen.