Twenty-four hours after Harald and Karen landed in England, the photographs Harald had taken at the radar station on Sande had been printed, enlarged, and pinned up on one wall of a big room in a grand building in Westminster. Some had been marked with arrows and notes. In the room were three men in RAF uniforms, examining the pictures and talking in low, urgent voices.

Digby Hoare ushered Harald and Karen into the room and closed the door, and the officers turned around. One of them, a tall man with a gray moustache, said, "Hello, Digby."

"Good morning, Andrew," Digby said. "This is Air Vice Marshal Sir Andrew Hogg. Sir Andrew, may I present Miss Duchwitz and Mr. Olufsen."

Hogg shook Karen's left hand, as her right was still in a sling. "You're an exceptionally brave young woman," he said. He spoke English with a clipped accent that made him sound as if he had something in his mouth, and Harald had to listen hard to understand him. "An experienced pilot would hesitate to cross the North Sea in a Hornet Moth," Hogg added.

"To tell the truth, I had no idea how dangerous it was when I set off," she replied.

Hogg turned to Harald. "Digby and I are old friends. He's given me a full report on your debriefing, and frankly I can't tell you how important this information is. But I want you to go over again your theory about how these three pieces of apparatus work together."

Harald concentrated, retrieving from his memory the English words he needed. He pointed to the general shot he had taken of the three structures. "The large aerial rotates steadily, as if constantly scanning the skies. But the smaller ones tilt up and down and side to side, and it seemed to me they must be tracking aircraft."

Hogg interrupted him to say to the other two officers, "I sent a radio expert on a reconnaissance flight over the island this morning at dawn. He picked up waves of two point four meters wavelength, presumably emanating from the big Freya, and also fifty-centimeter waves, presumably from the smaller machines, which must be Wurtzburgs." He turned back to Harald. "Carry on, please."

"So I guessed that the large machine gives long-range warning of the approach of bombers. Of the smaller machines, one tracks a single bomber, and the other tracks the fighter sent up to attack it. That way, a controller could direct a fighter to the bomber with great accuracy."

Hogg turned to his colleagues again. "I believe he's right. What do you think?"

One of them said, "I'd still like to know the meaning of himmelbett."

Harald said, "Himmelbett? That's the German word for one of those beds . . ."

"A four-poster bed, we call it in English," Hogg told him. "We've heard that the radar equipment operates in a himmelbett, but we don't know what that means."

"Oh!" said Harald. "I've been wondering how they would organize things. This explains it."

The room went quiet. "Does it?" said Hogg.

"Well, if you were in charge of German air defense, it would make sense to divide your borders up into blocks of airspace, say five miles wide and twenty miles deep, and assign a set of three machines to each block . . . or himmelbett."

"You might be right," Hogg said thoughtfully. "That would give them an almost impenetrable defense."

"If the bombers fly side by side, yes," said Harald. "But if you made your RAF pilots fly in line, and sent them all through one single himmelbett, the Luftwaffe would be able to track only one bomber, and the others would have a much better chance of getting through."

Hogg stared at him for a long moment. Then he looked at Digby, and at his two colleagues, then back at Harald.

"Like a stream of bombers," Harald said, not sure they understood.

The silence stretched out. Harald wondered if there was something wrong with his English. "Do you see what I mean?" he said.

"Oh, yes," said Hogg at last. "I see exactly what you mean."

On the following morning Digby drove Harald and Karen out of London to the northeast. After three hours they arrived at a country house that had been commandeered by the air force as officers' quarters. They were each given a small room with a cot, then Digby introduced them to his brother, Bartlett.

In the afternoon they all went with Bart to the nearby RAF station where his squadron was based. Digby had arranged for them to attend the briefing, telling the local commander it was part of a secret intelligence exercise; and no further questions were asked. They listened as the commanding officer explained the new formation the pilots would use for that night's raid - the bomber stream.

Their target was Hamburg.

The same scene was repeated, with different targets, on airfields up and down eastern England. Digby told Harald that more than six hundred bombers would take part in tonight's desperate attempt to draw some of the Luftwaffe's strength back from the Russian front.

The moon rose a few minutes after six o'clock in the evening, and the twin engines of the Wellingtons began to roar at eight. On the big blackboard in the operations room, takeoff times were noted beside the code letter for each aircraft. Bart was piloting G for George.

As night fell, and the wireless operators reported in from the bombers, their positions were marked on a big map table. The markers moved ever closer to Hamburg. Digby smoked one anxious cigarette after another.

The lead aircraft, C for Charlie, reported that it was under attack from a fighter, then its transmissions stopped. A for Able approached the city, reported heavy flak, and dropped incendiaries to light the target for the bombers following.

When they began to drop their bombs, Harald thought of his Goldstein cousins in Hamburg, and hoped they would be safe. As part of his schoolwork last year he had had to read a novel in English, and he had chosen War in the Air by H. G. Wells, which had given him a nightmare vision of a city under attack from the air. He knew this was the only way to defeat the Nazis, but all the same he dreaded what might happen to Monika.

An officer came over to Digby and said in a quiet voice that they had lost radio contact with Bart's aircraft. "It may just be a wireless problem," he said.

One by one, the bombers called in to report that they were heading back - all but C for Charlie and G for George.

The same officer came over to say, "The rear gunner of F for Freddie saw one of ours go down. He doesn't know which, but I'm afraid it sounds like G for George."

Digby buried his face in his hands.

The counters representing the aircraft moved back across the map of Europe on the table. Only C and G remained over Hamburg.

Digby made a phone call to London, then said to Harald, "The bomber stream worked. They're estimating a lower level of losses than we've had for a year."

Karen said, "I hope Bart's all right."

In the early hours, the bombers began to come back in. Digby went outside, and Karen and Harald joined him, watching the big aircraft land on the runway and disgorge their crews, tired but jubilant.

When the moon went down, they were all back but Charlie and George.

Bart Hoare never did come home.

Harald felt low as he undressed and put on the pajamas Digby had loaned him. He should have been jubilant. He had survived an incredibly dangerous flight, given crucial intelligence to the British, and seen the information save the lives of hundreds of airmen. But the loss of Barty's aircraft, and the grief on Digby's face, reminded Harald of Arne, who had given his life for this, and Poul Kirke, and the other Danes who had been arrested and would almost certainly be executed for their parts in the triumph; and all he could feel was sadness.

He looked out of the window. Dawn was breaking. He drew the flimsy yellow curtains across the little window and got into bed. He lay there, unable to sleep, feeling bad.

After a while Karen came in. She, too, was wearing borrowed pajamas, with the sleeves and the trousers rolled to shorten them. Her face was solemn. Without speaking, she climbed into bed next to him. He held her warm body in his arms. She pressed her face into his shoulder and began to cry. He did not ask why. He felt sure she had been having the same thoughts as he. She cried herself to sleep in his arms.

After a while he drifted into a doze. When he opened his eyes again, the sun was shining through the thin curtains. He gazed in wonderment at the girl in his arms. He had often daydreamed about sleeping with her, but he had never foreseen it quite like this.

He could feel her knees, and one hip that dug into his thigh, and something soft against his chest that he thought might be a breast. He watched her face as she slept, studying her lips, her chin, her reddish eyelashes, her eyebrows. He felt as if his heart would burst with love.

Eventually she opened her eyes. She smiled at him and said, "Hello, my darling." Then she kissed him.

After a while, they made love.

Three days later, Hermia Mount appeared.

Harald and Karen walked into a pub near the Palace of Westminster, expecting to meet Digby, and there she was, sitting at a table with a gin and tonic in front of her.

"But how did you get home?" Harald asked her. "Last time we saw you, you were hitting Detective Constable Jespersen over the head with your suitcase."

"There was so much confusion at Kirstenslot that I was able to slip away before anyone noticed me," Hermia said. "I walked into Copenhagen under cover of darkness and reached the city at sunrise. Then I came out the way I had gone in: Copenhagen to Bornholm by ferry, then a fishing boat across to Sweden, and a plane from Stockholm."

Karen said, "I'm sure it wasn't as easy as you make it sound."

Hermia shrugged. "It was nothing compared with your ordeal. What a journey!"

"I'm very proud of you all," said Digby, though Harald thought, by the fond look on his face, that he was especially proud of Hermia.

Digby looked at his watch. "And now we have an appointment with Winston Churchill."

An air raid warning sounded as they were crossing Whitehall, so they met the Prime Minister in the underground complex known as the Cabinet War Rooms. Churchill sat at a small desk in a cramped office. On the wall behind him was a large-scale map of Europe. A single bed covered with a green quilt stood against one wall. He was dressed in a chalk-stripe suit and had taken off the jacket, but he looked immaculate.

"So you're the lass who flew the North Sea in a Tiger Moth," he said to Karen, shaking her left hand.

"A Hornet Moth," she corrected him. The Tiger Moth was an open aircraft. "I think we might have frozen to death in a Tiger Moth."

"Ah, yes, of course." He turned to Harald. "And you're the lad who invented the bomber stream."

"One of those ideas that came out of a discussion," he said with some embarrassment.

"That's not the way I heard the story, but your modesty does you credit." Churchill turned to Hermia. "And you organized the whole thing. Madam, you're worth two men."

"Thank you, sir," she said, although Harald could tell by her wry smile that she did not think that was much of a compliment.

"With your help, we have forced Hitler to withdraw hundreds of fighter aircraft from the Russian front and bring them back for the defense of the fatherland. And, partly thanks to that success, it may interest you to know that I have today signed a co-belligerency pact with the Union of Soviet Socialist Republics. Britain no longer stands alone. We have as an ally one of the world's greatest powers. Russia may be bowed, but she is by no means beaten."

"My God," said Hermia.

Digby murmured, "It will be in tomorrow's papers."

"And what are you two young people thinking of doing next?" Churchill asked.

"I'd like to join the RAF," Harald said immediately. "Learn to fly properly. Then help to free my country."

Churchill turned to Karen. "And you?"

"Something similar. I'm sure they won't let me be a pilot, even though I can fly much better than Harald. But I'd like to join the women's air force, if there is one."

"Well," said the Prime Minister, "we have an alternative to suggest to you."

Harald was surprised.

Churchill nodded to Hermia, who said, "We want you both to go back to Denmark."

It was the one thing Harald had not been expecting. "Go back?"

Hermia went on, "First, we'd send you on a training course - quite long, six months. You'd learn radio operation, the use of codes, handling firearms and explosives, and so on."

Karen said, "For what purpose?"

"You'd parachute into Denmark equipped with radio sets, weapons, and false papers. Your task would be to start a new Resistance movement, to replace the Nightwatchmen."

Harald's heart beat faster. It was a remarkably important job. "I had my heart set on flying," he said. But the new idea was even more exciting - though dangerous.

Churchill intervened. "I've got thousands of young men who want to fly," he said brusquely. "But so far we haven't found anyone who could do what we're asking of you two. You're unique. You're Danish, you know the country, you speak the language as natives, which you are. And you have proved yourselves quite extraordinarily courageous and resourceful. Let me put it this way: If you don't do it, it won't be done."

It was hard to resist the force of Churchill's will - and Harald did not really want to. He was being offered the chance to do what he had longed for, and he was thrilled at the prospect. He looked at Karen. "What do you think?"

"We'd be together," she said, as if that was the most important thing for her.

"Then you'll go?" said Hermia.

"Yes," said Harald.

"Yes," said Karen.

"Good," said the Prime Minister. "Then that's settled."