A little seaside town just like this one . . . I thought about the German guns I had heard yesterday, and the radio announcement about the thousands of men trapped on the beaches. Just twenty miles away. I squinted at the horizon to try to see the outline of the French coast.

The sky was clearer than it had been the day before, but there was a strange haze over the water. It wasn’t a sea mist, though – it was smoke. Something rumbled in the distance and we saw the tiny silhouette of a plane moving across the sky, but it was too far away for us to see if it was ours or the enemy’s.

‘It was that newspaper article about the Treachery Act that really upset him,’ I said.

Mags nodded – she had seen the article too.

‘He thinks they are going to prosecute her,’ I said. ‘He thinks they’ll find her guilty.’

Mags shook her head, furious. ‘But what proof have they got?’

‘They don’t need proof, Mags.’ And my voice sounded like it belonged to someone else. ‘They’ve got her confession.’

‘Her confession?’

My heart was beating in my throat as I passed my sister the piece of paper that I had tucked beneath my pillow.

‘What’s that? Another letter from Mutti?’

I shook my head. ‘It’s the same letter. This is the second page. I found it on Pa’s desk last night, hidden underneath yesterday’s newspaper.’

‘He hid it from us?’

‘Yes.’ I recalled the shocked expression on Pa’s face when I had walked into the kitchen, and the peculiar way in which Mutti’s letter had ended: P.S. Remember . . .

Mags read the missing second page:

‘ . . . that I have told the detective everything he needs to know. I am ready now to write everything down and sign it. I will write that I am guilty. This is really the best way. I love you all so much.

‘But she can’t be a spy! Not our Mutti . . .’

‘I know,’ I said.

When Mags gave the piece of paper back to me, I saw that her hand was shaking, just like mine.

She must have noticed the same thing. She put her arm around me and squeezed me hard. She hadn’t hugged me for months. Suddenly I couldn’t hold back my tears any longer.

‘I don’t understand any of it, Mags,’ I sobbed.

‘No,’ she said.‘But if she’s making a confession to the police, she must have done something, mustn’t she?’

Pinstripe’s ominous words echoed through me: Sometimes, good people do bad things . . . This is something you are going to need to come to terms with. Very soon.

Perhaps he had received her written confession already. I pulled away from my sister, wiped my eyes with my sleeve and sat still for a moment.

‘What do you think will happen?’

‘I don’t know.’