We usually went to my nan’s cottage at least twice a week. Her house was very small and my mum was always worrying that my nan would be lonely, because she had lived on her own ever since my granddad had died, ten years ago, but there were always other people in my nan’s house, wandering through the door directly into the living room without knocking: my cousin Donna, my aunt Carol and uncle Bob, my aunt Fiona and my uncle Paul with my new cousin Pete, and Bob’s mum Pat and Paul’s mum Irene. The cottage had Artex ceilings that reminded me of nougat and a gas fire with pretend plastic coal in it and a kitchen counter with red and white cigarette packets and the googly-eyed Gnasher the Dog badge on it and a bigger telly than ours and backless stairs and a mantlepiece with a photo of my granddad, who I’d never met because he was dead, standing in a river in big wellies holding a fishing rod, and a glass of water in the bathroom where my nan kept her teeth at night. Everyone was always competing for my nan’s attention, especially me and Donna, and to prevent us from squabbling, my mum and her sister, my aunt Carol, had decided that Donna and I would take turns to spend Christmas with her. Now my cousin Pete had been born, though, it would all get more complicated, and I’d only get my nan for Christmas once every three years. The reason my nan had a googly-eyed Gnasher the Dog badge was because I had made her join the Dennis the Menacefan club with me, but that was mainly so I could get a reserve googly-eyed Gnasher the Dog badge in case mine got lost or damaged. I had thought that maybe the Dennis the Menacefan club might not let my nan in, because she was almost fifty-three, but they did. Donna could talk to my nan about almost anything, including Dennis the Menaceand Gnasher, but she couldn’t talk to her about snooker, which was where I had the upper hand. I enjoyed few things more than watching snooker on my nan’s telly, and even though it was black and white and the balls were all different colours, that didn’t matter at all, because we saw them as coloured in our heads while we watched. When summer arrived I also liked watching tennis with my nan, but this month she was sad because one of her favourite players, Björn Borg, had retired, even though he was too young to retire. My nan never got angry, unless she saw Margaret Thatcher, the prime minister, on the TV, and even then didn’t swear, although I could tell she wanted to and sometimes was trying so hard not to that tiny bits of spit came out of her mouth. After the first time the aliens had tried to take me back, and I’d been very ill in hospital, with tubes in lots of parts of my body, my nan’s kind, smiling face had been the first thing I’d seen when I had woken up, and that’s how I’d known that on that occasion the aliens had not succeeded in their mission to abduct me.

The doctors and nurses called what I’d had a ‘burst appendix’. They said if my dad had not acted as quickly as he had and driven me to the hospital as fast as he did in our crap Morris Traveller, which he’d hastily bought to replace the actually superior Morris Minor, then run into the hospital with me in his arms, like a quicker version of the way he didn’t actually carry the lifeless body of Flo Tansy to the pond across the road from our house, I would have been dead because the poison that was seeping into my belly would have become too much for my body to cope with and stopped my heart. I accepted the explanation, and felt lucky to have such a great and quick-thinking dad, but I knew the real reason I’d almost died was because the aliens were trying to get to me through my stomach. After my dad had run into the hospital from the car park with me in his arms, a doctor and two nurses had put me on a table with wheels and taken me to a big white room, then another doctor had injected me with a needle and told me to count to ten, and when I’d counted very nearly to seven, and everything was going blurry, I’d seen a man with a scalpel and, behind him, another man who had a normal face at first but whose fake smile and whole face then started to stretch really wide, like it was made of rubber, and I knew that had been one of the aliens. I don’t know why his quest to get me had failed and the doctors had won and managed to save me, but ever since then I had been vigilant, ready for something like that to happen again, and knew it was purely a matter of time before it did. From my experience in the operating theatre, it was obvious that the aliens were adept at shapeshifting, which meant I had to be extra vigilant.

It had taken many weeks for me to recover from the aliens using the method of bursting my appendix to capture me and take me back to their own planet. I had been very frail for a long time and had to learn to walk again, almost from scratch. That was almost three years ago and, when I thought about who I was, everything in the time before my appendix burst was a little blurred: the operation was, and would increasingly become, a dry stone wall separating one part of my childhood from another. I wasn’t yet tall enough to see over the wall, and although there were various gaps, little pockets of air between the stones, it was difficult to find them and I usually had to peer really hard through a kind of thick rain to see what was on the other side. I definitely remembered nursery school, and going to Twycross Zoo with my mum and dad and Donna and Carol and Bob, and a holiday where all the rooms were in a circle around a big hall, but there was other stuff I was less clear about: a small potato with a face in a fluffy duffle coat standing next to a Morris Minor, a photo of my nan, in tears of laughter, holding a baby in tears of tears. Who was that potato? Who was that baby? Was it me? How long had I actually been here?

‘Nather,’ I said one night, a couple of weeks before going on holiday with my parents to Cumberland Which Was Actually Now Cumbria. (This was what I sometimes called my nan, as well as ‘Nan’, ‘Terry’ and ‘Nantwich’.)

‘Hello,’ my nan replied. (‘Hello’ was often her way of saying ‘Yes’ or ‘I’m here’ as well as her way of saying ‘Hello’.)

‘Do you remember me as a baby?’

‘Of course I do, you silly sausage.’

‘What do you remember about me?’

‘Oh, you were so sweet. Always so bright-eyed, curious about everything. But you used to cry when you came here at first, so much, and you cried even more if your mum and dad were late picking you up. You’d lie on your back, kick at the wall and let rip, wailing your head off, and I’d worry that Mr Jameson next door would think I had been torturing you. The rest of the time, though, butter wouldn’t melt. You worried so much when you dropped your panda in the lake at Newstead Abbey, you thought he might have drowned.’

‘I don’t remember a panda.’

A car hurtled up the hill outside, blasting a novelty horn, the same as one on a TV show I liked.

‘The world’s gone mad, son,’ said my nan, shaking her head.

While my nan made my bed that night, I studied myself in the oval mirror in her living room. Sometimes grown-ups said I was ‘sweet’, and when the headteacher at one of my dad’s schools had seen me she had said, ‘Oh, who is this handsome man?’ but that was not how I viewed my predicament. What I saw staring back at me now was what I always saw in mirrors and photos of myself: a mathematical concoction of an idea of a small male human. It wasn’t a word that I knew then, but I think the best way I could put it would be to say I viewed myself as ‘generic’. I saw it at home, in my head, every day, and I saw it at school, as I looked at those diverse, interesting-looking children all around me, the ones preserved for posterity in that wonderful class photo, so brimful of life: I was not real. Others, such as my nan, my mum, my dad and my friends, might have been fooled – unless they, too, were in on it, which I had not discounted – but I knew the truth. The evidence was in some innate part of me, and right in front of everyone’s face: I looked like an idea of a young boy, one that was a little too neat, which could only have been made by people from another planet trying to make a human. Oh, they’d messed up the nose a bit, made it a bit too squashed and little and weird, but even that, I knew, was deliberate: another clever part of their subterfuge. I might not have any memory of where I was from, and some of the other details were unclear to me, such as when exactly I’d arrived, why I was here, how much my parents knew about it all, and what I’d look like when the aliens came back and got me, but what I did know was that I did not belong here and soon I would return to my home planet.