An idea has settled over me and I can’t shake it off. If you’re a writer, you’ll be familiar with the signs: the queasy excitement, drifting focus, the sense of impending doom. The curse is come upon me, cried the Lady of Shalott. A story looms.

I keep asking whether I have to write it. Will it fuck off and leave me alone, or will it be there every morning at 4 a.m., watching me sleep, waiting to pounce as soon as I open my eyes. Can I pare it down to nothing, write it and be done? Or will i...