Pinned to the window, I can’t tear my eyes away. When finally it’s over, Fräulein Müller climbs back into the car and it pulls away. Vati stands for a moment watching it travel down the road, his hands in his pockets. Then he turns towards the house. The iron gate creaks shut behind him.

*

My head throbs as I wake to strong morning light – I’d forgotten to close my shutters last night before crawling into bed. Coming downstairs, I see that I’ve missed breakfast and Mutti has gone out. A new worry awakens. Should I tell Mutti what I saw? The thought sends a wave of horror through me. Bertha makes me some warm milk and hands me a plate of sausage and bread.

‘Morning, sleepy,’ Karl says as he comes into the kitchen.

‘I need to talk to you about something,’ I whisper when Bertha moves towards the sink. ‘In private.’

‘Okay. Treehouse?’ He raises his eyebrows.

We sit on the floor, sharing the bread and sausage, a blanket wrapped around our shoulders. Despite the temperature, it’s cosy in our secret nest, just the two of us.

‘Should I tell Mutti?’ I ask quietly, after recounting what I saw.

He shakes his head. ‘You must have dreamed it, Hetty. You have a crazy imagination.’

‘But I was awake, Karl, I saw them. It was horrible.’

‘You’re being ridiculous. It was the middle of the night. You fell asleep in your window seat and had a bad dream. Besides, why would Vati want to kiss Fräulein Müller? She looks like a heifer with those massive hindquarters.’ He begins to laugh. ‘Moo,’ he says, blowing out his cheeks and making his eyes all big.

Perhaps he is right. I could have dreamed it. Suddenly, I have a picture of a brown-patched cow with Fräulein Müller’s round face and fierce plaits where its ears should be.

‘Moo,’ I say, giggling.

‘Moo, Herr Heinrich, how about a kiss?’ Karl laughs and curls up his top lip, just like a cow smelling the air.

I’m laughing so hard my eyes begin to water. Karl digs me in the ribs with his elbow.

‘See?’ he says. ‘See how silly it all is?’

Ingrid’s fair head appears at the base of the tree.

‘Walter Keller is at the door to see you,’ she calls up to Karl.

Racehorse hooves thud in my chest.

Karl’s forehead creases. I expect him to throw the blanket off his shoulders and bolt down the ladder, ending our private chat. But his body is completely still.

‘Tell him I’m not here,’ he shouts down to Ingrid. To my astonished face he explains, ‘I have to go out soon. Meeting some of my HJ friends.’

His serious face cracks into a smile and he pushes me onto the dusty treehouse floor, tickling me hard under the armpits.

‘Stop it! I don’t want to play that game,’ I yell, fighting him off.

‘What’s the matter?’

‘Why did you send Walter away?’