I put my elbows on my knees, my head into my hands. Dimly aware that, somewhere behind me, a door closed. I wanted to vomit but there was nothing there. Out of the corner of my eye I saw Mum doing something on her tablet. There was a loud click and then she was speaking.

‘Gareth, I have locked Ashleigh and myself in the media room. You cannot come in. Do not try to override the security program. It won’t work because the system will only answer to me. My daughter and I are going to have a conversation and I am going to explain everything to her. It may take time. It will take time.’

‘Chrissie …’ Dad’s voice. Worried. Hurt.

‘I’m turning off our communication channels now. Wait for us.’

Silence.

Mum was pacing in front of the media screen. I could only see her legs moving one way and then the other. It was really strange. There was a buzzing in my head.

‘Ashleigh, look at the screen.’

I lifted my head. It didn’t really matter if I lifted my head or not. There was a map of Australia up on the screen, but it was a strange and distorted one, bigger than the proper map. I recognised it from lessons at school.

‘This was Australia at the beginning of the twenty-first century, Ashleigh.’ Mum was off to my right but I didn’t look in her direction. I just stared at the screen. She must have pressed something on her tablet because the image changed to the real map, the familiar map, a bit like the old one but shrunk around many of the edges.

‘Rising sea levels, caused by global warming that melted the icecaps, did this to Australia in a very short period of time. A crazy percentage of people, eighty-five per cent is the accepted estimate, lived within fifty kilometres of the coast. Twenty million Australians, most of whom, over time, became homeless. You know this from school, right?’

I didn’t say anything. I was fixated on the map. I couldn’t see where home was. Mum waited a few seconds and then carried on.

‘Some tried to migrate to other countries, but nearly all were turned back. Many people died at sea in ferocious storms that swept most of the world.’ She gave a strange and twisted laugh. ‘Historians have often said that’s ironic since successive Australian governments had banned migration to Australia by boat. Now we needed help, but found we had to reap what we had sown.’