She opened the door as quietly as possible.

She peeped in. She could see no one. She stepped inside and looked all around. The room was empty.

There was no sign of Joachim’s canvas bag.

She looked at the double door that led to the study. One of the two doors stood half open.

Carla tiptoed across the room. There was no carpet here, just polished wood blocks, and her footsteps were not completely silent; but she had to take the risk.

As she got nearer, she heard whispers.

She reached the doorway. She flattened herself against the wall then risked a look inside.

They were standing up, embracing, kissing. Joachim had his back to the door and to Carla: no doubt Maud had taken care to move him into that position. As Carla watched, Maud broke the kiss, looked over his shoulder, and caught Carla’s eye. She took her hand away from Joachim’s neck and made an urgent pointing gesture.

Carla saw the canvas bag on a chair.

She understood immediately what had gone wrong. When Maud had inveigled Joachim into the study, he had not obliged them by leaving his bag in the drawing room, but had nervously taken it with him.

Now Carla had to retrieve it.

Heart thudding, she stepped into the room.

Maud murmured: ‘Oh, yes, keep doing that, my sweet boy.’

Joachim groaned: ‘I love you, my darling.’

Carla took two paces forward, picked up the canvas bag, turned around, and stepped silently out of the room.

The bag was light.

She walked quickly across the drawing room and ran down the stairs, breathing hard.

In the kitchen she put the bag on the table and unbuckled its straps. Inside were today’s edition of the Berlin newspaper Der Angriff, a fresh pack of Kamel cigarettes, and a plain buff-coloured cardboard folder. With trembling hands she took out the folder and opened it. It contained a carbon copy of a document.

The first page was headed:

DIRECTIVE NO. 41

On the last page was a dotted line for a signature. Nothing was penned there, no doubt because this was a copy, but the name typed beside the line was Adolf Hitler.

In between was the plan for Case Blue.

Exultation rose in her heart, mingled with the tension she already felt and the terrible dread of discovery.

She put the document on the low cupboard next to the kitchen window. She jerked open the drawer and took out the Minox camera and the two spare films. She positioned the document carefully, then began to photograph it page by page.

It did not take long. There were just ten pages. She did not even have to reload film. She was done. She had stolen the battle plan.

That was for you, Father.

She put the camera back in the drawer, closed the drawer, slipped the document into the cardboard folder, put the folder back in the canvas bag, and closed the bag, fastening the straps.

Moving as quietly as she could, she carried the bag back upstairs.