By 1939, he was head of the criminal intelligence department of the Cologne police. In May 1940, when General Heinz Gudenan's panzer tanks crossed the river Meuse at Sedan and swept triumphantly through France to the English Channel in a week, Dieter impulsively applied for a commission in the army. Because of his police experience, he was given an intelligence posting immediately. He spoke fluent French and adequate English, so he was put to work interrogating captured prisoners. He had a talent for the work, and it gave him profound satisfaction to extract information that could help his side win battles. In North Africa his results had been noticed by Rommel himself.

He was always willing to use torture when necessary, but he liked to persuade people by subtler means. That was how he had got Stephanie. Poised, sensual, and shrewd, she had been the owner of a Paris store selling ladies' hats that were devastatingly chic and obscenely expensive. But she had a Jewish grandmother. She had lost the store and spent six months in a French prison, and she had been on her way to a camp in Germany when Dieter rescued her.

He could have raped her. She had certainly expected that. No one would have raised a protest, let alone punished him. But instead, he had fed her, given her new clothes, installed her in the spare bedroom in his apartment, and treated her with gentle affection until one evening, after a dinner of foie de veau and a bottle of La Tache, he had seduced her deliciously on the couch in front of a blazing coal fire.

Today, though, she was part of his camouflage. He was working with Rommel again. Field Marshal Erwin Rommel, the "Desert Fox," was now Commander of Army Group B, defending northern France. German intelligence expected an Allied invasion this summer. Rommel did not have enough men to guard the hundreds of miles of vulnerable coastline, so he had adopted a daring strategy of flexible response: his battalions were miles inland, ready to be swiftly deployed wherever needed.