‘Does it mean transformation?’ Someone at the back breaks the silence. I twist around and glimpse a small girl with frizzy black hair, a little like my own.

‘Name please,’ Dr Kreitz says, his head popping up, eyes bulging out, reminding me of a frog.

‘Freda Federmann,’ says the girl in a confident voice.

‘Wonderful. Yes, Freda.’ Dr Kreitz enthuses. ‘Transformation. Rebirth. Conversion. From the Greek, Metamorphoun, meaning, “To transform”.’ He begins to pace. ‘Studying the Greeks and Romans,’ he says, ‘will teach us all we need to know about the human condition.’

‘Freda Federmann is a Jewess,’ I hear someone hiss to her neighbour from the row behind me. It’s loud enough for the professor to hear, but he shows no sign of it. He picks a book up from the table as he passes by.

The professor has narrow shoulders and a pot belly. Part of his shirt hangs from his trousers and his tie is askew. This school, famous for its classical education, clearly picked him for his knowledge and superior brain, not for his appearance.

‘Franz Kafka,’ he says, staring intently up at the ceiling, as though he might see the author perched on top of the rafters. ‘What a brilliant – and amusing – man he was. Listen.’ He vigorously flicks through some pages, his hair flopping wildly. He begins to read, treading a slow circuit of the room. He tells us, in a mesmerising voice, the story of Gregor, the travelling salesman who awakens one morning to find himself transformed into an enormous insect-like creature.

Light filters through the long, rectangular windows set high up on the classroom wall. Adolf Hitler stares serenely down at us all from his vast portrait above the blackboard. Dr Kreitz’s voice rises and falls, fades and resounds. As I look at the portrait, Hitler’s face appears to swell and move. He gazes at me, unblinking, but I’m certain his lips have moved, twitched, as if at any moment, he might smile and step down from the picture, saying, Ha ha, what a joke, I have been here all along.

He doesn’t, of course, and I tear my eyes away. Karl says I have too much imagination. My heart jumps and I wonder if he’s right.

Dr Kreitz reads on. I avoid looking at Hitler’s picture and instead study the profile of the girl sitting next to me. Tall and elegant, she has long auburn hair which hangs either side of her shoulders in two smooth plaits. Her pale face is so perfectly formed, it could have been chiselled from the finest marble. She holds her chin high as she watches Dr Kreitz travel around the room. Feeling my gaze, she turns and fixes me with sloping green eyes.

‘Hello,’ she whispers. ‘My name is Erna Bäcker.’ A smile flickers on her lips.

‘Hetty Heinrich,’ I reply, excruciatingly aware of my frizzy dark hair, big eyes and too-round cheeks.

Erna Bäcker is simply the most bewitching creature I have ever seen in my life.