I had always rather liked Mrs Baron, but right now she was my least favourite person on the whole planet – after Mags, of course. I glared at my sister and tried not to make eye contact with Mutti and Pa, who were smiling at me proudly as if I had been picked to play the lead part in the school play. I noticed Mrs Baron’s handsome sixteen-year-old son Michael was also smiling, and I hoped that my cheeks weren’t too beetroot-red.

Then I realized that Mrs Baron’s eagle-eyes had settled expectantly upon me and I hadn’t been listening to a single word she had been saying.

‘Off you go, Petra,’ she said, gesturing to the mask I was clutching in my hands.

I knew exactly what was going to happen next. What always happened to me when I was this frightened. I froze.

Mrs Baron sighed. ‘Like this, dear . . .’ And quite suddenly she had taken the gas mask out of my rigid hands, pressed it on to my face and was pulling the tight strap over the top of my head.

I was underwater. I was drowning.

The village hall became a sinking ship, swaying its way down to the bottom of the deepest, greenest sea, taking me and everyone else with it. My whole head was pinched with pressure and I gasped for air, hearing a strange, alien hiss as I managed to draw in a little dizzying oxygen, just enough to keep me alive for a few agonizing seconds, until, at last, I felt a hand on the back of my head pulling the strap off again – and then – oh, the relief! – I could breathe once more – I could move! I folded in half, hands on my shaking knees, tongue hanging out of my mouth, trying to inhale enough clean air to get rid of the bitter, rubbery taste of the mask.

‘Are you all right, Petra?’ Mrs Baron said, rubbing my back soothingly. ‘It is a bit odd at first, I know, but don’t worry – you’ll get used to it with practice!’ She gave a sympathetic little laugh and everyone else in the village hall laughed too.

My face burnt with embarrassment as I made my way unsteadily out of the door along with the rest of the village, my gas mask safely back in its cardboard box. I took a deep, cool breath of the seaside air and turned my face up towards the sun, as if its light could somehow bleach away the horror of the last few minutes.

‘You did well, Petra,’ said a voice beside me. I turned to see Michael Baron’s sparkling green eyes looking down at me. ‘I felt quite queasy the first time I tried to breathe through one of these. Tastes horrible, doesn’t it?’