Harald thought the Tiger Moth was the most beautiful machine he had ever seen. It looked like a butterfly poised for flight, its upper and lower wings spread wide, its toy-car wheels resting lightly on the grass, it long tail tapering behind. The weather was fine with gentle breezes, and the little aircraft trembled in the wind, as if eager to take off. It had a single engine in the nose driving the big cream-painted propeller. Behind the engine were two open cockpits, one in front of the other.

It was cousin to the dilapidated Hornet Moth he had seen in the ruined monastery at Kirstenslot, and the two aircraft were mechanically similar, except that the Hornet Moth had an enclosed cabin with seats side by side. However, the Hornet Moth had looked sorry for itself, leaning to one side on its broken undercarriage, its fabric torn and oil-stained, its upholstery bursting. By contrast, the Tiger Moth had a sprightly look, with new paint bright on its fuselage and the sun glinting off its windscreen. Its tail rested on the ground and its nose pointed up, as if it were sniffing the air.

"You'll notice that the wings are flat underneath but curved above," said Harald's brother, Arne Olufsen. "When the aircraft is moving, the air traveling over the top of the wing is forced to move faster than the air passing underneath." He gave the engaging grin that made people forgive him anything. "For reasons I have never understood, this lifts the aircraft off the ground."

"It creates a pressure difference," Harald said.

"Indeed," Arne replied dryly.

The senior class at Jansborg Skole were spending the day at the Army Aviation School at Vodal. They were being shown around by Arne and his friend Poul Kirke. It was a recruiting exercise by the army, who were having trouble persuading bright young men to join a military force that had nothing to do. Heis, with his army background, liked Jansborg to send one or two pupils into the military each year. For the boys, the visit was a welcome break from exam revision.

"The hinged surfaces on the lower wings are called ailerons," Arne told them. "They are connected by cables to the control column, which is sometimes called the joystick, for reasons you are too young to understand." He grinned again. "When the stick is moved to the left, the left aileron moves up and the right one down. This causes the aircraft to tilt and turn left. We call it banking."

Harald was fascinated, but he wanted to get in and fly.

"You'll observe that the rear half of the tailplane is also hinged," Arne said. "This is called the elevator, and it points the aircraft up or down. Pull back on the stick and the elevator tilts up, depressing the tail, so that the aircraft climbs."

Harald noticed that the upright part of the tail also had a flap. "What's that for?" he asked, pointing at it.

"This is the rudder, controlled by a pair of pedals in the footwell of the cockpit. It works in the same way as the rudder of a boat."

Mads put in, "Why do you need a rudder? You use the ailerons to change direction."

"Good point!" Arne said. "Shows that you're listening. But can't you figure it out? Why would we need a rudder as well as ailerons to steer the aircraft?"

Harald guessed. "You can't use the ailerons when you're on the runway."

"Because . . . ?"

"The wings would hit the ground."

"Correct. We use the rudder while taxiing, when we can't tilt the wings because they would hit the ground. We also use the rudder in the air, to control unwanted sideways movement of the aircraft, which is called yaw."

The fifteen boys had toured the air base, sat through a lecture - on opportunities, pay, and training in the army - and had lunch with a group of young pupil pilots. Now they were eager for the individual flying lesson which had been promised to each of them as the climax of the day. Five Tiger Moths were lined up on the grass. Danish military aircraft had been officially grounded since the beginning of the occupation, but there were exceptions. The flying school was allowed to give lessons in gliders, and special permission had been granted for today's exercise in Tiger Moths. Just in case anyone had the idea of flying a Tiger Moth all the way to Sweden, two Messerschmitt Me-109 fighter aircraft stood on the runway, ready to give chase and shoot down anyone who tried to escape.

Poul Kirke took over the commentary from Arne. "I want you to look into the cockpit, one at a time," he said. "Stand on the black walkway on the lower wing. Don't step anywhere else or your foot will go through the fabric and you won't be able to fly."

Tik Duchwitz went first. Poul said: "On the left side you see a silver-colored throttle lever, which controls the speed of the engine, and lower down a green trim lever which applies a spring loading to the elevator control. If the trim is correctly set when cruising, the aircraft should fly level when you take your hand off the stick."

Harald went last. He could not help being interested, despite his resentment of the smoothly arrogant way Poul had swept Karen Duchwitz off on her bicycle.

As he stepped down, Poul said, "So, what do you think, Harald?"

Harald shrugged. "It seems straightforward."

"Then you can go first," Poul said with a grin.

The others laughed, but Harald was pleased.

"Let's all get kitted up," Poul said.

They returned to the hangar and put on flying suits - step-in overalls that buttoned in front. Helmets and goggles were also given out. To Harald's annoyance, Poul made a point of helping him.

"Last time we met was at Kirstenslot," Poul said as he adjusted Harald's goggles.

Harald nodded curtly, not wishing to be reminded. Still, he could not help wondering exactly what Poul's relationship with Karen was. Were they just dating, or something more? Did she kiss him passionately and let him touch her body? Did they talk of getting married? Had they had sexual intercourse? He did not want to think about these things, but he could not help it.

When they were ready, the first five students returned to the field, each with a pilot. Harald would have liked to go up with his brother, but once again Poul chose Harald. It was almost as if he wanted to get to know Harald better.

An airman in oily overalls was refueling the aircraft, standing with one foot in a toehold in the fuselage. The tank was in the center of the upper wing where it passed above the front seat - a worrying position, Harald felt. Would he be able to forget the gallons of inflammable fluid over his head?

"First, the preflight inspection," Poul said. He leaned into the cockpit. "We check that the magneto switches are off and the throttle is closed." He looked at the wheels. "Chocks in place." He kicked the tires and wiggled the ailerons. "You mentioned that you had worked on the new German base at Sande," he said casually.

"Yes."

"What sort of work?"

"Just general laboring - digging holes, mixing concrete, carrying bricks."

Poul moved to the back of the aircraft and checked the movement of the elevators. "Did you find out what the place is for?"

"Not then, no. As soon as the basic construction work was done, the Danish workers were dismissed, and the Germans took over. But I'm pretty sure it's a radio station of some kind."

"I think you mentioned that last time. But how do you know?"

"I've seen the equipment."

Poul looked at him sharply, and Harald realized this was no casual inquiry. "Is it visible from outside?"

"No. The place is fenced and guarded, and the radio equipment is screened by trees, except on the side facing the sea, and that part of the beach is off limits."

"So how come you saw it?"

"I was in a hurry to get home, so I took a shortcut across the base."

Poul crouched down behind the rudder and checked the tail skid shoe. "So," he said, "what did you see?"

"A large aerial, the biggest I've ever come across, maybe twelve feet square, on a rotating base."

The airman who had been refueling the aircraft interrupted the conversation. "Ready when you are, sir."

Poul said to Harald, "Ready to fly?"

"Front or back?"

"The trainee always sits in the back."

Harald climbed in. He had to stand on the bucket seat then ease himself down. The cockpit was narrow, and he wondered how fat pilots managed, then he realized there were no fat pilots.

Because of the nose-up angle at which the aircraft sat on the grass, he could see nothing in front of him but the clear blue sky. He had to lean out to one side to see the ground ahead.

He put his feet on the rudder pedals and his right hand on the control stick. Experimentally, he moved the stick from side to side and saw the ailerons move up and down at his command. With his left hand he touched the throttle and trim lever.

On the fuselage just outside his cockpit were two small knobs which he assumed were the twin magneto switches.

Poul leaned in to adjust Harald's safety harness. "These aircraft were designed for training, so they have dual controls," he said. "While I'm flying, rest your hands and feet lightly on the controls and feel how I'm moving them. I'll tell you when to take over."

"How will we talk?"

Poul pointed to a Y-shaped rubber pipe like a doctor's stethoscope. "This works like the speaking tube on a ship." He showed Harald how to fix the ends to earpieces in his flying helmet. The foot of the Y was plugged into an aluminum pipe which undoubtedly led to the front cockpit. Another tube with a mouthpiece was used for speaking.

Poul climbed into the front seat. A moment later Harald heard his voice through the speaking tube. "Can you hear me?"

"Loud and clear."

The airman stood by at the left front of the aircraft, and a shouted dialogue ensued, with the airman asking questions and Poul answering.

"Ready to start, sir?"

"Ready to start."

"Fuel on, switches off, throttle closed?"

"Fuel is on, switches are off, throttle is closed."

Harald expected the airman to turn the propeller at that point, but instead he moved to the right side of the aircraft, opened the cowling panel in the fuselage, and fiddled with the engine - priming it, Harald assumed. Then he closed the panel and returned to the nose of the aircraft.

"Sucking in, sir," he said, then he reached up and pulled the propeller blade down. He repeated the action three times, and Harald guessed this procedure drew fuel into the cylinders.

The airman reached over the lower wing and flicked the two little switches just outside Harald's cockpit. "Throttle set?"

Harald felt the throttle lever move forward half an inch under his hand, then heard Poul say, "Throttle set."

"Contact."

Poul reached out and flicked the switches forward of his cockpit.

Once again the airman swung the propeller, this time stepping back smartly immediately afterward. The engine fired and the propeller turned. There was a roar, and the little aircraft trembled. Harald had a sudden vivid sense of how light and frail it was, and remembered with a sense of shock that it was made, not of metal, but of wood and linen. The vibration was not like that of a car or even a motorcycle, which felt solid and firmly grounded by comparison. This was more like climbing a young tree and feeling the wind shake its slender branches.

Harald heard Poul's voice over the speaking tube. "We have to let the engine warm up. It takes a few minutes."

Harald thought about Poul's questions on the subject of the base at Sande. This was not idle curiosity, he felt sure. Poul had a purpose. He wanted to know the strategic importance of the base. Why? Was Poul part of some secret Resistance movement? What else could it be?

The engine note rose, and Poul reached out and turned the magneto switches off and on again in turn - performing yet another safety check, Harald assumed. Then the note declined to idling pitch, and at last Poul signaled to the airman to remove the wheel chocks. Harald felt a lurch, and the aircraft moved forward.

The pedals at his feet moved as Poul used the rudder to steer the aircraft across the grass. They taxied to the runway, which was marked by little flags, and turned into the wind, then they stopped, and Poul said, "A few more checks before we take off."

For the first time, it occurred to Harald that what he was about to do was dangerous. His brother had been flying for years without an accident, but other pilots had crashed, and some had died. He told himself that people died in cars, on motorcycles, and aboard boats - but somehow this felt different. He made himself stop thinking about the dangers. He was not about to panic and disgrace himself in front of the class.

Suddenly the throttle lever beneath his hand moved smoothly forward, the engine roared louder, and the Tiger Moth eagerly moved along the runway. After only a few seconds, the control stick eased away from Harald's knees, and he felt himself tip forward slightly as the tail lifted behind him. The little aircraft gathered speed, rattling and shaking over the grass. Harald's blood seemed to thrill with excitement. Then the stick eased back under his hand, the aircraft seemed to jump from the ground, and they were airborne.

It was exhilarating. They climbed steadily. To one side, Harald could see a small village. In crowded Denmark, there were not many places from which you could not see a village. Poul banked right. Feeling himself tipped sideways, Harald fought the panicky notion that he was going to fall out of the cockpit.

To calm himself, he looked at the instruments. The rev counter showed two thousand rpm, and their speed was sixty miles per hour. They were at an altitude of one thousand feet already. The needle on the turn-and-slip indicator pointed straight up.

The aircraft straightened out and leveled off. The throttle lever moved back, the engine note dipped, and the revs slipped back to nineteen hundred. Poul said, "Are you holding the stick?"

"Yes."

"Check the line of the horizon. It probably goes through my head."

"In one ear and out the other."

"When I release the controls, I want you to simply keep the wings level and the horizon in the same place relative to my ears."

Feeling nervous, Harald said, "Okay."

"You have control."

Harald felt the aircraft come alive in his hands, as every slight movement he made affected its flight. The line of the horizon fell to Poul's shoulders, showing that the nose had lifted, and he realized that a barely conscious fear of diving to the ground was making him pull back on the stick. He pushed it forward infinitesimally, and had the satisfaction of seeing the horizon line slowly rise to Poul's ears.

The aircraft lurched sideways and banked. Harald felt he had lost control and they were about to fall out of the sky. "What was that?" he cried.

"Just a gust of wind. Correct for it, but not too much."

Fighting back panic, Harald moved the stick against the direction of bank. The aircraft lurched in the other direction, but at least he felt he was controlling it, and he corrected again with another small movement. Then he saw that he was climbing again, and brought the nose down. He found he had to concentrate fiercely on responding to the aircraft's slightest motion just to keep a steady course. He felt that a mistake could send him crashing to the ground.

When Poul spoke, Harald resented the interruption. "That's very good," Poul said. "You're getting the hang of it."

Harald felt he just needed to practice for another year or two.

"Now press lightly on the rudder pedals with both feet," Poul said.

Harald had not thought about his feet for a while. "All right," he said brusquely.

"Look at the turn-and-slip indicator."

Harald wanted to say, For God's sake, how can I do that and fly the aircraft at the same time? He forced himself to take his eyes off the horizon for a second and look at the instrument panel. The needle was still in the twelve noon position. He looked back at the horizon and found that he had lifted the nose again. He corrected.

"When I take my feet off the rudder, you'll find the nose will yaw left and right with the turbulence. In case you're not sure, check the indicator. When the aircraft yaws left, the needle will move to the right, telling you to press down with your right foot to correct."

"All right."

Harald felt no sideways movement, but a few moments later, when he managed to steal a glance at the dial, he saw he was yawing left. He pressed down on the rudder pedal with his right foot. The needle did not move. He pressed harder. Slowly, the pointer edged back to the central position. He looked up and saw that he was diving slightly. He pulled the stick back. He checked the turn-and-slip indicator again. The needle was steady.

It would have seemed simple and easy if he had not been fifteen hundred feet up in the air.

Poul said, "Now let's try a turn."

"Oh, shit," said Harald.

"First, look left to see if there's anything in the way."

Harald glanced to the left. In the far distance he could see another Tiger Moth, presumably with one of his classmates aboard, doing the same as he. That was reassuring. "Nothing nearby," he said.

"Ease the stick to the left."

Harald did so. The aircraft banked left and he again experienced the sickening feeling that he was going to fall out. But the aircraft began to swing around to the left, and Harald felt a surge of excitement as he realized he was actually steering the Tiger Moth.

"In a turn, the nose tends to dip," Poul said. Harald saw that indeed the aircraft was heading downward, and he pulled back on the stick.

"Watch that turn-and-slip indicator," Poul said. "You're doing the equivalent of a skid."

Harald checked the dial and saw that the needle had moved to the right. He pressed the rudder pedal with his right foot. Once again, it responded only slowly.

The aircraft had turned through ninety degrees, and Harald was eager to straighten up and feel safe again, but Poul seemed to read his mind - or perhaps all pupils felt the same way at this point - and said, "Keep turning, you're doing fine."

The angle of bank seemed dangerously steep to Harald but he held the turn, keeping the nose up, checking the slip indicator every few seconds. Out of the corner of his eye he noticed a bus driving along the road below, just as if nothing in the least dramatic was happening in the sky, and there was no danger of a Jansborg schoolboy dropping out of the heavens to his death on its roof.

He had turned through three-quarters of a circle before Poul at last said, "Straighten up."

With relief, Harald eased the stick right, and the aircraft straightened.

"Watch that slip indicator."

The needle had moved left. Harald pressed the rudder pedal with his left foot.

"Can you see the airfield?"

At first Harald could not. The countryside beneath him was a meaningless pattern of fields dotted with buildings. He had no idea what the air base would look like from above.

Poul helped him out. "A row of long white buildings beside a bright green field. Look to the left of the propeller."

"I see it."

"Head that way, keeping the airfield on the left of our nose."

Until now, Harald had not thought about the course they were following. It had been all he could manage to keep the aircraft steady. Now he had to do all the things he had previously learned and at the same time head for home. There was always one thing too many to think about.

"You're climbing," Poul said. "Throttle back an inch and bring us down to a thousand feet as we approach the buildings."

Harald checked the altimeter and saw that the aircraft was indeed at two thousand feet. It had been fifteen hundred last time he looked. He throttled back and eased the stick forward.

"Dip the nose a bit more," said Poul.

Harald felt the aircraft was in danger of diving vertically to the ground, but he forced himself to push the stick farther forward.

"Good," said Poul.

By the time they were at a thousand feet, the base was below them.

"Turn left around the far side of that lake and bring us in line with the runway," Poul ordered.

Harald leveled out and checked the slip indicator.

As he drew parallel with the end of the lake, he moved the stick left. This time, the feeling that he was going to fall out was not so bad.

"Watch that slip indicator."

He had forgotten. Correcting with his foot, he brought the aircraft around.

"Throttle back an inch."

Harald brought the lever back, and the engine note dipped sharply.

"Too much."

Harald eased it forward again.

"Dip the nose."

Harald pushed the control stick forward.

"That's it. But try to keep heading for the runway."

Harald saw that he had wandered off course and was headed for the hangars. He put the aircraft into a shallow turn, correcting with the rudder, then lined it up with the runway again. But now he could see that he was too high.

"I'll take over from here," Poul said.

Harald had thought Poul might talk him through a landing, but clearly he had not gained sufficient control for that. He felt disappointed.

Poul closed the throttle. The engine note fell abruptly, giving Harald the worrying feeling that there was nothing to keep the aircraft from falling straight down, but in fact it glided gradually to the runway. A few seconds before touchdown, Poul eased the stick back. The aircraft seemed to float along a few inches above the earth. Harald felt the footwell pedals moving constantly, and realized Poul was steering with the rudder now that they were too close to the ground to dip a wing. At last there was a bump as the wheels and the tailskid touched earth.

Poul turned off the runway and taxied toward their parking space. Harald was thrilled. It had been even more exciting than he had imagined. He was also exhausted from concentrating so hard. It had only been a short time, he thought, then he glanced at his watch, and saw to his astonishment that they had been airborne for forty-five minutes. It had felt like five.

Poul shut down the engine and climbed out. Harald pushed back his goggles, took off his helmet, fumbled with his safety harness, and struggled out of his seat. He stepped onto the reinforced strip on the wing and jumped to the ground.

"You did very well," said Poul. "Showed quite a talent for it, in fact - just like your brother."

"I'm sorry I couldn't bring it in to the runway."

"I doubt if any of the other boys will even be allowed to try. Let's go and get changed."

When Harald had got out of his flying suit, Poul said, "Come to my office for a minute." Harald went with him to a door marked "CHIEF FLYING INSTRUCTOR" and entered a small room with a filing cabinet, a desk, and a couple of chairs.

"Would you mind making a drawing of that radio equipment you were describing to me earlier?" Poul's tone was casual, but his body was stiff with tension.

Harald had wondered whether that subject would come up again. "Sure."

"It's quite important. I won't go into the reasons why."

"That's all right."

"Sit at the desk. There's a box of pencils and some paper in the drawer. Take your time. Do it over until you're satisfied."

"Okay."

"How long do you think you might need?"

"Maybe a quarter of an hour. It was dark so I can't draw details. But I have a clear outline in my head."

"I'll leave you alone so you don't feel pressured. I'll come back in fifteen minutes."

Poul left and Harald began to draw. He cast his mind back to that Saturday night in the pouring rain. There had been a circular concrete wall, he recalled, about six feet high. The aerial had been a grid of wires looking like bedsprings. Its rotating base was inside the circular wall, and cables had run from the back of the aerial into a duct.

First he drew the wall with the aerial above. He vaguely recalled that there had been one or two similar structures nearby, so he sketched them in lightly. Then he drew the machinery as if the wall were not there, showing its base and the cables. He was no artist but he could render machinery accurately, probably because he liked it.

When he had finished, he turned the sheet of paper over and made a plan of the island of Sande, showing the position of the base and the restricted area of beach.

Poul came back after fifteen minutes. He studied the drawings intently, then said, "This is excellent - thank you."

"You're welcome."

He pointed to the ancillary structures Harald had sketched. "What are these?"

"I really don't know. I didn't look closely. But I thought I should put them in."

"Quite right. One more question. This grid of wires, which is presumably an aerial. Is it flat, or dished?"

Harald racked his brains, but could not remember. "I'm not sure," he said. "Sorry."

"That's all right." Poul opened the filing cabinet. All the files were labeled with names, presumably of past and present pupils at the school. He selected one marked "Andersen, H.C." It was not an unusual name, but Hans Christian Andersen was Denmark's most famous writer, and Harald guessed the file might be a hiding place. Sure enough, Poul put the drawings in the folder and returned the file to its place.

"Let's go back to the others," he said. He went to the door. Stopping with his hand on the doorknob, he said, "Making drawings of German military installations is a crime, technically. It would be best not to mention this to anyone - not even Arne."

Harald felt a pang of dismay. His brother was not involved in this. Even Arne's best friend did not think he had the nerve.

Harald nodded. "I'll agree to that - on one condition."

Poul was surprised. "Condition? What?"

"That you tell me something honestly."

He shrugged. "All right, I'll try."

"There is a Resistance movement, isn't there?"

"Yes," Poul said, looking serious. After a moment's pause, he added, "And now you're in it."