“I see,” Churchill’ said thoughtfully. “So even though you have the book in front of you”-he pointed to the Disassembled chunks of turbine again-“you cannot simply read off what is on its pages, but must decode it as if it were written in a cipher.”

“That’s a good analogy, sir,” Hipple said. “The facts of the engine are relatively straightforward, even if we can’t yet produce one identical to it ourselves. When it comes to the radar from the same downed aircraft, I fear we are still missing a great many code groups, so to speak.”

“So I have been given to understand,” Churchill said, “although I do not fully grasp where the difficulty lies.”

“Let me take you over to Radarman Goldfarb, then, sir,” Hipple said. “He joined the team to help emplace a radar set in production Meteors, and has labored valiantly to unlock the secrets of the Lizard unit that fell into our hands.”

As the group captain brought the Prime Minister over to his workbench, Goldfarb thought, not for the first time, that Fred Hipple was a good man to work for. A lot of superior officers would have done all the explaining to the brass themselves, and pretended their subordinates didn’t exist. But Hipple introduced Goldfarb to Churchill, then stood back and let him speak for himself.

He didn’t find it easy at first. When he stammered, the Prime Minister shifted the subject away from radar: “Goldfarb,” he said musingly. “Was I not told you are the lad with a family connection to Mr. Russie, the former Lizard spokesman from Poland?”

“Yes, that’s true, sir,” Goldfarb answered. “We’re cousins. When my father came to England before the Great War, he urged his sister and her husband to come with him, and he kept urging them to get out until the second war started in ‘39. They wouldn’t listen to him, though. Moishe Russie is their son.”

“So your family kept up the connection, then?”

“Till the war cut us off, yes, sir. After that, I didn’t know what had happened to any of my relatives until Moishe began speaking on the wireless.” He didn’t tell Churchill most of his kinsfolk had died in the ghetto; the Prime Minister presumably knew that already. Besides, Goldfarb couldn’t think about their fate without filling up with a terrible anger that made him wish England were still at war with the Nazis rather than the Lizards.

Churchill said, “I shan’t forget this link. It may yet prove useful for us.” Before Goldfarb could work up the nerve to ask him how, he swung back to radar: “Suppose you explain to me how and why this set is so different from ours, and so baffling.”

“I’ll try, sir,” Goldfarb said. “One of our radars, like a wireless set, depends on valves-vacuum tubes, the Americans would say-for its operation. The Lizards don’t use valves. Instead, they have these things.” He’ pointed to the boards with little lumps and silvery spiderwebs of metal set across them.

“And so?” Churchill said. “Why should a mere substitution pose a problem?”

“Because we don’t know how the bloody things work,” Goldfarb blurted. Wishing the ground would open up and swallow him, he tried to make amends: “That is, we have no theory to explain how these little lumps of silicon-which is what they are, sir-can perform the function of valves. And, because they’re nothing like what we’re used to, we’re having to find out what each one does by cut and try, so to speak: we run power into it and see what happens. We don’t know how much power to use, either.”

Churchill fortunately took his strong language in stride. “And what have you learnt from your experiments?”

“That the Lizards know more about radar than we do, sir,” Goldfarb answered. “That’s the long and short of it, I’m afraid. We can’t begin to make parts to match these: a chemical engineer with whom I’ve spoken says our best silicon isn’t pure enough. And some of the little lumps, when you look at them under a microscope, are so finely etched that we can’t imagine how, let alone why, it’s been done.”

“How and why are for those with the luxury of time, which we have not got,” Churchill said. “We need to know what the device does, whether we can match it, and how to make it less useful to the foe.”

“Yes, sir,” Goldfarb said admiringly. Churchill was no boffin, but he had a firm grip on priorities. No one yet fully understood the theory of the magnetron, or how and why the narrow channels connecting its eight outer holes to the larger central one exponentially boosted the strength of the signal. That the device operated so, however, was undeniable fact, and had given the RAF a great lead over German radar-although not, worse luck, over what the Lizards used.

Group Captain Hipple said, “What have we learnt which is exploitable, Goldfarb?”

“Sorry, sir; I should have realized at once that was what the Prime Minister needed to know. We can copy the design of the Lizards’ magnetron; that, at least, we recognize. It gives a signal of shorter wavelength and hence more precise direction than any we’ve made ourselves. And the nose dish that receives returning pulses is a very fine bit of engineering which shouldn’t be impossible to incorporate into later marks of the Meteor.”

“Very good, Radarman Goldfarb,” Churchill said. “I shan’t keep you from your work any longer. With the aid of men like you and your comrades in this hut, we shall triumph over this adversity as we have over all others. And you, Radarman, you may yet have a role to play even more important than your work here.”

The Prime Minister looked uncommonly cherubic. Three years in the RAF had taught Goldfarb that rankers who wore that expression had more up their sleeves than their arms. They’d also taught him he couldn’t do anything about it, so he said what he had to say: “I’ll be happy to serve in any way I can, sir.”

Churchill nodded genially, then went back to Hipple and his colleagues for more talk about jet engines. After another few minutes, he put his hat back on, tipped it to Hipple, and left the Nissen hut.

Basil Roundbush grinned at Goldfarb. “I say, old man, after Winnie makes you an MP, do remember the little people who knew you before you grew rich and famous.”

“An MP?” Goldfarb shook his head in mock dismay. “Lord, I hope that’s not what he had in mind. He said he had something important instead of this.”

That sally met with general approval. One of the meteorologists said, “Good job you didn’t tell him you’re a Labour supporter, Goldfarb.”

“It doesn’t matter, not now.” Goldfarb had backed Labour, yes, as offering more to the working man than the Tories could (and, as was true of a lot of Jewish immigrants and their progeny, his own politics had a slant to the left). But he also knew no one but Churchill could have rallied Britain against Hitler, and no one else could have kept her in the fight against the Lizards.

Thinking of the Nazis and the Lizards together made Goldfarb think of the invasion so many had feared in 1940. The Germans hadn’t been able to bring it off, not least because radar kept them from driving the RAF from the skies. If the Lizards came, no one could offer any such guarantee of success. Ironically, the Germans holding northern France served as England’s shield against invasion by the aliens.

But the shield was not perfect. The Lizards had control of the air when they chose to use it. They could leapfrog over northern France and the Channel both. Just because, they hadn’t done it didn’t mean they wouldn’t or couldn’t.

Goldfarb snorted. The only thing he could do about that was try to make British radar more effective, which would in turn make the Lizards pay more if they decided to invade. It wasn’t as much as he’d have wanted to do in an ideal world, but it was more than most people could say, so be supposed it would do.

And he’d not only met Winston Churchill, but talked business with him! That wasn’t something everyone could say. He couldn’t write home to his family that the Prime Minister had been here-the censors would never pass it-but he could tell them if he ever got down to London. He’d almost given up on the notion of leave.