The beam of the lighthouse blares down upon the rocks. It warns sailors away, yes, but it also illuminates the sullen outcrop where you and I dance, a nightly ritual to ward off the angry spirits of those shipwrecked in the dark years before the lighthouse was built. We two are merely the latest. Dancers have performed at this bleak coast each night for longer than anyone can recall.

In recent evenings, my dancing has been poor, slack, lazy. You’ve told me this yourself and though I turned away from you, I knew that you were right. So tonight I am doing my utmost to perform with grace, poise and determination. But you aren’t. You’ve never once not danced carefully and precisely, feet perfectly pointed in your pale pink shoes, not a toe out of place. But tonight you flail and thrash, as if trying to attract spirits, not repel them.

Fishermen perch on rocks nearby, cheering you on, and they jeer when I am eventually forced to break my routine and grab at you, my jaw set hard against the salty wind. But you simply break away and carry on, lost within your frenzy: twirling, whirling, laughing, shrieking, clapping. The fishermen clap too, strong hands beating out a rhythm that rips the night apart. Then something twists in my mind and suddenly I understand what has happened. Because my dancing has been inattentive, the ritual has not been performed effectively these past few days. Coming out here to dance, night after night, in all weathers, is a chore. Is it any wonder I grew apathetic? I’ve been missing steps here, there and everywhere, ignoring the purpose of the ritual. Clearly I have caused the spell to fail and the spirits have taken you. You, who danced like some creature of heaven, have been possessed. It is so unfair, yet this is the only explanation for your behaviour and it’s my fault. Now I must do something, this moment, before the evil spreads like a virus.

As you skip past me, face gnarled and crooked, I hesitate for just a moment, but then I see the void in your eyes and the threat in your smile, and I cross myself and shove you into the ocean. I hear your skull crack as you bounce from the rocks and disappear beneath the surface. I crumple to my knees. Tears burn my eyes.

The clapping halts. The fishermen stare at each other, then rise and stride towards me. They yell words like ‘devil’ and ‘fiend’, spittle spraying over their beards. I want to say no, no, it wasn’t me, she was the demon, not me, her, my sister, but now, somehow, I cannot even open my mouth, and I think about my sibling, who I have just murdered, and I realise that I am just as cursed as she, and so are this mob advancing upon me. I have invited evil to this place and it has accepted.

I’m forced to the edge of the outcrop. Illuminated by the lighthouse, a pale pink dance shoe floats to the surface of the black water.