A second later he cocked his leg over the edge of the slates and rolled up onto the roof.

He splayed his body out, for maximum traction, then reached down. With one gloved hand he grabbed the collar of Rebecca’s coat, and she grasped his upper arm.

The curtains were suddenly pulled apart, and a woman’s face stared at Rebecca from a distance of a few inches.

The woman screamed.

With an effort, Bernd lifted Rebecca until she was able to get her leg over the sloping edge of the roof; then he pulled her toward him until she was safe.

But they both lost control and started to slide down.

Rebecca spread her arms and pressed the palms of her gloved hands to the slates, trying to brake her slide. Bernd did the same. But they continued to slip, slowly but relentlessly—then Rebecca’s sneakers touched an iron gutter. It did not feel sturdy, but it held, and they both came to a stop.

“What was that scream?” Bernd asked urgently.

“A woman in the bedroom saw me. I don’t think she could have been heard on the street, though.”

“But she might raise the alarm.”

“Nothing we can do. Let’s keep going.”

They edged crabwise across the pitched roof. The houses were old and some of the roof slates were broken. Rebecca tried not to put weight on the gutter that her feet were touching. Their progress was painfully slow.

She imagined the woman at the window talking to her husband. “If we do nothing we’ll be accused of collaborating. We could say we were fast asleep and didn’t hear anything, but they’ll probably arrest us anyway. And even if we call the police they might arrest us on suspicion. When things go wrong they arrest everyone in sight. Best just to keep our heads down. I’ll draw the curtains again.”

Ordinary people avoided any contact with the police—but the woman at the window might not be ordinary. If she or her husband was a party member, with a soft job and privileges, they would have a degree of immunity from police harassment, and in those circumstances they would undoubtedly raise a hue and cry.

But the seconds ticked by, and Rebecca heard no sound of a commotion. Perhaps she and Bernd had got away with it.

They came to an angle in the roof. Bracing his feet on the opposing sides, Bernd was able to crawl upward until he got his hands over the roof ridge. Now he had a safer grip, though he ran the risk that his dark-gloved fingertips might be noticed by the police on the street.

He turned the angle and crawled on, every second getting nearer to Bernauer Strasse and freedom.

Rebecca followed. She glanced over her shoulder, wondering if anyone could see her and Bernd. Their dark clothing was inconspicuous against the gray slates, but they were not invisible. Was anyone watching? She could see the backyards and the cemetery. The dark figure she had noticed a minute ago was now running from the chapel toward the cemetery gate. A leaden fear made her stomach cold. Had he seen them, and was he hurrying to warn the police?