The only person.

 I have never saw a zombie eat human flesh. They like flesh well but they prefer to buy it from Tesco's meat counter, or the butcher's shop. I was the only one suspecting that an invasion was being staged by aliens. The clues that led to my deduction were first noticed in Tesco.

She appeared to be an elderly woman with a limp, gray curly hair, about five foot tall, a tired face, and a raincoat. She stood at the checkout before me, when I noticed that she had bought an abnormal amount of vodka and four aspirin bottles not that this shows in itself that the woman was not of this age, it's just an example of the kind of information I'm trained to find. I suppose you wonder what is a normal amount of vodka? For a little old lady, three half-liter bottles seemed a bit too much.

Standing behind her as we waited for our turn – the till's computer interfering with my wiring – I became more and more certain, until finally I couldn't contain myself anymore and shouted loudly at the top of my voice: that they had landed among us and it was plain to see that they were shopping among us without fear. That was when I felt the aliens were evil anyway. But the alien disguised as an old lady was the only one who tried to help me when the zombies of the security guard arrived behind me, though I was uncertain how they could see me, and tried to turn me off and force me out of the store before I could even pay for my victual. She said that if I went in front of her, she didn't mind making me pay for myself. I thanked her, and said nothing else about her interplanetary presence. I figured before I could turn her in, I would try to find out more about her. Though she seemed pretty sweet, she might have been sent here to support us. I always wanted to find out more. That was my program.

I paid in silence for my products and waited outside the store, before I saw her shuffling, dragging her shopping trolley behind her. What could fold down was one of those PVC affairs. I have tracked her from a discreet distance. I placed a jumper over my head to be sure she didn't see me I am always invisible. Yet, aliens, can see me. The old lady had looked at me. So I will my pullover over my head to prevent her from seeing me, as I have said. This made it hard to walk; but not impossible, because through the loose-knit wool I could still see quite a bit. And that's how we continued through town: pulling her cart in front of her; away from me behind, hidden within my jumper.

I Don't know why I was expecting the zombies to care for a foreigner. I was almost fooled by the illusion of my emotion, but no-one else seemed to be taken in. The zombie on the till at the seven things or under checkout didn't even blink when I yelled the discovery that there was intelligent life in the world, I supposed, they supposed it was. All the other zombies remained still in the queue. Zombie eyes, eyes which are dead, always avoid mine. Although I am dead too, or rather not alive. Maybe I used to be alive, but sometimes I became a robot who thinks he's human; then I hear the gear and I remember.

They had to have done the procedure in the night. I do not remember anything about it. I woke up. It was a different place. I examined my body closely but they had done a decent job on me, I could hardly tell I wasn't a human anymore. I still needed to eat and shit, but if I had ever been one, I was not a person anymore. I'm a robot. Although she apparently knew beforehand, I was not consulted and surprised by the transformation, as robots can be. My programming limits My reactions. My wiring was humming and my main valves were opening and closing faster than they now tend to.

I had been waiting for orders, but none had come. Created and surrendered. My decisions seemed to be exactly that, but all robots are programmed to that. We are all things copies. Imperfect copies of the  wrong stuff. I couldn't find the person I was based on. Maybe I did replace him. I remember that his wife left him ... me ... but whose memory is that? Whether the instructions are my own or created for me, I am continuing.

She never moved very quickly, nor did I. We advanced gradually. The jumper has had the added bonus of shielding me from rain. We made it to a block of flats. She had gone by the time I entered them. Perhaps I just lost her to the lift. She couldn't see me through the jumper so it was unlikely she gave me the slip.

Aliens wanted us to experiment with breeding so I had read. They wouldn't find me very useful in that department, because the designers didn't copy that dimension of the person on which I was based. I don't remember the last time I had my clothes taken off.

In what was probably a puddle of piss, I sat down on the floor; took the jumper off my head; picked up a piece of broken glass, and tried to open my wrist. I looked up; there was an alien standing before me. I gave up trying to open my wrist. My plan, let me stand up. I pursued her to her place. She said she wanted to take me home. I've told her which world it was. She made a cup of tea, and she did not respond. I was drinking tea; there may have been chemicals in it. I disengaged myself. When I woke up, I saw the old woman pouring her vodka down the sink. Occasionally, extraneous behavior was puzzling. I was not prepared for this. I asked her for how long she 'd spent on this planet. She said she did not know, and had recently changed plans to move. I asked her if she'd ever experiment with me. She said if that meant cooking, then yes, she 'd definitely experiment on me. I didn't remember the last time I had eaten, or what I did with the Tesco stuff I got. I informed her that I was glad she wanted to live a little longer on earth. I asked her if she'd like more. She said she was the only one, as far as she was aware. I told her maybe there were two of me here.