March thought: of all of us, Halder has changed the least. Beneath the layer of fat, behind the slackened muscle of incipient middle age, there lurked still the ghost of the gangling recruit, straight from university, who had joined the U-174 more than twenty years before. He had been a wireless operator — a bad one, rushed through training and into service at the start of 1942, when losses were at their height, and Donitz was ransacking Germany for replacements. Then as now, he wore wire-framed glasses and had thin ginger hair which stuck out at the back in a duck’s tail. During a voyage, while the rest of the men grew beards, Halder sprouted orange tufts on his cheeks and chin, like a moulting cat. The fact that he was in the U-boat service at all was a ghastly mistake, a joke. He was clumsy, barely capable of changing a fuse. He had been designed by nature to be an academic, not a submariner, and he passed each voyage in a sweat of fear and seasickness.

Yet he was popular. U-boat crews were superstitious, and somehow the word got around that Rudi Halder brought good luck. So they looked after him, covering his mistakes, letting him have an extra half-hour to groan and thrash around on his bunk. He became a sort of mascot. When peace came, astonished to find that he had survived, Halder resumed his studies at the history faculty of Berlin University. In 1958 he had joined the team of academics working at the Reichsarchiv on the official history of the war. He had come full circle, spending his days hunched in a subterranean chamber in Berlin, piecing together the same grand strategy of which he had once been a tiny, frightened component. The U-boat Service: Operations and Tactics, 1939-46 had been published in 1963. Now Halder was helping compile the third volume of the history of the German Army on the Eastern Front.

“It’s like working at the Volkswagen works in Fallersleben,” said Halder. He took a bite out of his egg and chewed for a while. “I do the wheels, Jaeckel does the doors, Schmidt drops in the engine.”

“How long is it going to take?”

“Oh, forever, I should think. Resources no object. This is the Arch of Triumph in words, remember? Every shot, every skirmish, every snowflake, every sneeze. Someone is even going to write the Official History of the Official Histories. Me, I’ll do another five years.” “And then?”

Halder brushed egg crumbs from his tie. “A chair in a small university somewhere in the south. A house in the country with Use and the kids. A couple of books, respectfully reviewed. My ambitions are modest. If nothing else, this kind of work gives you a sense of perspective about your own mortality. Talking of which…’From his inside pocket he pulled a sheet of paper. “With the compliments of the Reichsarchiv.”

It was a photocopy of a page from an old Party directory. Four passport-sized portraits of uniformed officials, each accompanied by a brief biography, Brun, Brunner. Buch. And Buhler.

Halder said: “Guide to the Personalities of the NSDAP. 1951 edition.”

“I know it well.”

“A pretty bunch, you’ll agree.”

The body in the Havel was Buhler’s, no question of it. He stared up at March through his rimless spectacles, prim and humourless, his lips pursed. It was a bureaucrat’s face, a lawyer’s face; a face you might see a thousand times and never be able to describe; sharp in the flesh, fudged in memory; the face of a machine-man.

“As you will see,” resumed Halder, “a pillar of National Socialist respectability. Joined the Party in “22 — that’s as respectable as they come. Worked as a lawyer with Hans Frank, the Fuhrer’s own attorney. Deputy President of the Academy of German Law.”

“ ‘State Secretary, General Government, 1939,’ ” read March.” ‘SS-Brigadefuhrer.’ ” Brigadefuhrer, by God. He took out a notebook and began to write.

“Honorary rank,” said Halder, his mouth full of food. “I doubt if he ever fired a shot in anger. He was strictly a desk man. When Frank was sent out as Governor in 39 to run what was left of Poland, he must have taken his old legal partner, Buhler, with him, to be chief bureaucrat. You should try some of this ham. Very good.”

March was scribbling quickly. “How long was Buhler in the East?”

Twelve years, I guess. I checked the Guide for 1952. There’s no entry for Buhler. So “51 must have been his last year.”

March stopped writing and tapped his teeth with his pen. “Will you excuse me for a couple of minutes?”

There was a telephone booth in the foyer. He rang the Kripo switchboard and asked for his own extension. A voice growled: “Jaeger.”

“Listen, Max.” March repeated what Halder had told him. “The Guide mentions a wife.” He held up the sheet of paper to the booth’s dim electric light and squinted at it. “Edith Tulard. Can you find her? To get the body positively identified.”

“She’s dead.”

“What?”

“She died more than ten years ago. I checked with the SS records bureau — even honorary ranks have to give next of kin. Buhler had no kids, but I’ve traced his sister. She’s a widow, seventy-two years old, named Elizabeth Trinkl. Lives in Furstenwalde.” March knew it: a small town about forty-five minutes” drive south-east of Berlin. “The local cops are bringing her straight to the morgue.”

“I’ll meet you there.”

“Another thing. Buhler had a house on Schwanen-werder.”

So that explained the location of the body. “Good work, Max.” March rang off and made his way back to the dining room.

Halder had finished his breakfast. He threw down his napkin as March returned and leaned back in his chair. “Excellent. Now I can almost tolerate the prospect of sorting through fifteen hundred signals from Kleist’s First Panzer Army.” He began picking his teeth. “We should meet up more often. Use is always saying: When are you going to bring Zavi round?” He leaned forward. “Listen: there’s a woman at the archives, working on the history of the Bund deutscher Madel in Bavaria, 1935 to 1950. A stunner. Husband disappeared on the Eastern front last year, poor devil. Anyway: you and she. What about it? We could have you both round, say next week?”

March smiled. “You’re very kind.”

“That’s not an answer.”

True.” He tapped the photocopy. “Can I keep this?”

Halder shrugged. “Why not?”

“One last thing.”

“Go ahead.”

“State Secretary to the General Government. What would he have done, exactly?”

Halder spread his hands. The backs were thick with freckles, wisps of reddish-gold hair curled from his cuffs. “He and Frank had absolute authority. They did whatever they liked. At that time, the main priority would have been resettlement.”

March wrote “resettlement” in his notebook, and ringed it. “How did that happen?”

“What is this? A seminar?” Halder arranged a triangle of plates in front of him — two smaller ones to the left, a larger one to the right. He pushed them together so they touched. “All this is Poland before the war. After “39, the western provinces” — he tapped the small plates — “were brought into Germany. Reichsgau Danzig-West Prussia and Reichsgau Wartheland.” He detached the large plate. “And this became the General Government. The rump state. The two western provinces were Germanised. It’s not my field, you understand, but I’ve seen some figures. In 1940, they set a target density of one hundred Germans per square kilometre. And they managed it in the first three years. An incredible operation, considering the war was still on.”

“How many people were involved?”

“One million. The SS eugenics bureau found Germans in places you’d never have dreamed of — Rumania, Bulgaria, Serbia, Croatia. If your skull had the proper measurements and you came from the right village — you were just given a ticket.”

“And Buhler?”

“Ah. Well. To make room for a million Germans in the new Reichsgaue, they had to move out a million Poles.”