I only realised that she was there when I looked at her. I wasn't supposed to; Mum and Dad had made it clear that I should never look out the window. But I was alone in my bedroom when she knocked, and I did look out, and down, to the garden, and I saw her. It was dark outside, but I saw her as clearly as if she were standing under the summer sun.
I noticed her hair first. It was long and red like Mum's, but unlike Mum's, it was messy and matted. Then I saw her fingers, which were long and slender like Dad's, but unlike Dad's, they were cut up and dirty. She wore a frayed white dress and she stood on the frozen ground with bare feet. She looked up at me. Her eyes were dark holes. She spoke. I heard no sound, but I read her thin, cracked lips. She said: Emma.
I went back into my room and then downstairs, where Mum and Dad were having biscuits and tea. The girl was banging on the door and sobbing. 'Who is she?' I asked.
Mum dropped her biscuit. Dad stopped stirring his tea and asked: 'Who is who?'
I pointed at the door. 'The girl. Her hair is like Mum's and her fingers are like yours. And she knows my name.'
Mum slapped her hands over her face and Dad said: 'There is no girl.'
Outside, the sobs became screams. The door was shaking under the force of the girl's fists. Mum uttered a muffled sob, stumbled up and rushed to the kitchen. Dad hunched his shoulders. 'There is no girl,' he repeated, and he picked up his cup but didn't drink. The girl was crying at the door and Mum was crying in the kitchen. I went back to my room and sat on my bed.
Mum came to talk to me first. She sat on the edge of my bed. She picked up my soft toy bunny, hugging it tight. 'We love you,' she said, and for a moment I thought she meant the bunny but of course she meant me.
'I know,' I said.
Mum stroked the bunny's head. 'We don't want to lose you.'
'No,' I said.
'You mustn't talk about the girl.'
'Is she my sister?' I asked.
'You mustn't look at her.'
'She has to be cold. It's snowing outside,' I said.
'You mustn't open the door for her.' Mum stopped stroking the bunny. 'Promise me that. Promise me that you will not open the door.'
I said nothing.
'Please,' said Mum, 'I can't bear to lose you again.'
'You never lost me before,' I said.
Mum hugged the bunny so tight that its body went flat. 'But I did,' she whispered, 'I did.'
She stood up, put the bunny on my pillow and pulled my blankets up. 'Go to sleep,' she said.
I lay down on the bed. Mum looked at me. A tear rolled over her cheek onto my pillow. 'I love you,' she said, and she left.
Dad came to talk to me next. He too sat on the edge of my bed, but he left the bunny alone.
'Some things are too difficult for a child to understand,' he said, 'That's why children should listen to their parents. So now, listen to me.'
'You mustn't talk about the girl,' said Dad.
'Mum already told me that.'
'You mustn't look at her.'
'Mum said that too.'
'You mustn't open the door for her,' said Dad.
'Why not?' I asked, 'She must be cold, and she should be with us. Is she not my sister?'
'She is no-one,' said Dad. 'Just an empty shell, rotting away. You have to understand. We love you. We couldn't bear to lose you. That's why we did it.'
'Did what?' I asked, but Dad didn't answer me. He reached for my hair as if he wanted to stroke it, but then pulled back his hand without touching me. 'Perhaps it was wrong,' he whispered. He stood up and left.
My sister came back at midnight. This time she didn't cry. She didn't bang on the door either, but I knew she was there. I went downstairs. The front door was locked but I walked through it anyway, and there was my sister, glaring at me with empty eye sockets.
'Hi,' I said.
She said nothing, but shuffled away, and around the house to the back garden. I followed her. She walked as if her legs were not properly attached to her body, over the dark lawn and to an open grave. I didn't remember there being a grave in the back garden, but there it was, complete with gravestone. There was an inscription on the gravestone.
'Emma' it read, 'Still with us in spirit'.
'Emma!' That was Mum. I looked up, and there she was, she and Dad, hand in hand behind their bedroom window. 'Emma!' called Dad.
I waved at them and then turned to the grave. My grave. My sister, who wasn't my sister after all, had climbed into it and was lying in a coffin at the bottom of the grave, looking quite like a corpse, and also quite like me.
'Yes.' I said, and I went after her, and we were one again.