I should have met Walter by the bridge last Sunday, as well as this morning, but the conversation I had with Ingrid after meeting Walter in town has rattled inside my head on and off ever since, and I daren’t go.

My throat tightens at the thought of him returned to Hindenburgstrasse, not knowing why I didn’t come last week or this. He’ll be worried. Perhaps he’ll think I don’t want to see him anymore, after our audacious city adventure, and he won’t bother to go back to the bridge next week. I toss and turn; doze and wake.

Damn the headache and damn Ingrid. After a couple of hours, the headache reduced to a dull throb, I go downstairs and find Mutti in the afternoon sitting room. In the days after Karl left, she became abstracted, as if when he went, he took a chunk of her with him too, and I began to worry if she was quite all right.

Now, to get over his absence, she’s thrown herself with renewed vigour into getting her children’s home up and running. She sits at the writing bureau, head bent, her pen scratching furiously as she writes letters to the Party, to the Mayor, to the newspapers. A faint, rapidly-speaking foreign voice comes from the new radio Vati has installed next to the gramophone. Sometimes, when Vati has left for work in the mornings, Mutti finds a French station and listens, as now, with her head inclined, a smile twitching on her lips. I cross the room and snap the machine off.

‘What did you do that for?’ Mutti jerks around and gives me a hurt look, as if I’ve roughly woken her from a pleasant dream.

‘Vati will be angry and forbid it if he catches you.’

‘But he won’t be back from Berlin until this evening.’ She sighs. ‘Working on a Sunday too.’ She arches her back and stretches her arms out behind as though she’s been hunched over her writing desk for many hours already.

‘What about Ingrid? Is she here?’ I stare at the doorway, in case she’s hovering just outside.

‘No, I’ve given her the whole day off. But what’s Ingrid got to do with it?’

I sigh with relief. The book will be safe beneath my mattress, for now anyway. ‘Why don’t we do something today, Mutti? Go out together. We could both do with some fresh air.’ She looks back to the letters on her desk.

‘I must finish these… Perhaps later.’ She gives me a quick smile. ‘There’s so much work to do, setting up one of these ventures. All the paperwork. And finding the children. One must do it right.’

‘What do you mean, finding the children? If they’re orphans, wouldn’t they just be handed in?’

‘I should say, finding the correct children. It’s sorting the desirable from… the others. They are developing tests, physical assessments, to check the purity of the children. They’re very thorough – sixty-two separate checks to be made on each child. It’s most rigorous. But it means we have to look far and wide to find appropriate children.’