At first, the woman in the corridor was a glimpse of white between the blue jumpers. She was walking in our direction, a head taller than the students around her. As we approached her, Cara stopped and seized my arm.

She wore a white gown to the floor with yellowed patches at the neck and armpits, and a rumpled quality which gave the impression that she hadn’t changed for many days. Her hair hung flat against her back and then dangled down to the knees. She was anxious in the hallway, turning this way and that, and flinching when a pupil came too close to her. Where she passed, the hubbub softened to a hum. It was the pitch of stage whispers, and feigned horror. She was gaunt other than for her jowls, and the hangs of her belly and breasts.

‘Oh my God,’ Cara said. ‘Is she OK?’

I realized with a slow, hot humiliation that the woman in the corridor was Mother.

‘Don’t worry,’ I said. ‘I know her.’

Cara turned to me, incredulous.

‘It’s my mother,’ I said. ‘Something must have happened.’

I considered my hard-won invisibility. Its cloak was beginning to slip, and in moments it would be on the floor.

‘I should find out,’ I said. ‘But break time tomorrow?’

Cara was backing away from me against the corridor wall. She took timid little steps in her school shoes, as though I might not notice her departure. Already, I knew, she was thinking about who might be her new best friend.

‘I’m sorry, Lex,’ she said. ‘I’m really sorry.’

Alone, I approached. Mother was trembling. ‘Is it Evie?’ I asked, and Mother shook her head. I hadn’t seen her outside the house for so long that I had forgotten her twitchiness. Without Father at her side, she moved like a cornered sheep, twisting for an escape. She placed a hand on my wrist and I saw her fingernails as the other children would see them. Not resting harmlessly on her duvet when we said goodnight, but overgrown and jaundiced, with shadows of dirt trapped beneath them.

‘Can we go somewhere else?’ she said. ‘The office was incompetent – I didn’t know where to find you.’

‘Of course.’

She fed her arm through my elbow, and the sea of children parted to let us pass. Cara would do well from this, I thought: she could testify to my secrecy, my strange habits. Her statements would be in high demand. Just before the door to the playground closed, I heard the eruption behind us.

Cara contacted me once, when I was living in London with JP. She had found me on LinkedIn, and hoped that we might connect. She didn’t mention Five Fields, and she didn’t refer to the events at Moor Woods Road. She was a solicitor too, she said. I hadn’t heard of the firm, and I didn’t respond to Cara, but not out of any sense of resentment. We had never had very much in common, other than being a little cleverer than our peers; since then I had met many clever people, and knew that it was an insufficient basis on which to build a friendship. If I had been kinder, I might have let her know that I didn’t begrudge her that day in the corridor. People have done far worse things to survive being a teenager.

Mother and I stood in the playground in near-darkness. The moorlands were already black against the sky. I could see flickers of lessons through the classroom windows. Across the road, older boys ran on the football pitches, orange beneath the floodlights.

‘What happened?’ I asked.

‘It’s Father,’ Mother said. ‘He hasn’t come home.’

He had driven to one of Jolly’s sermons that morning, before sunrise. He had kissed Mother through her half-sleep, and touched her stomach, like a charm. He would be home for lunch. I tried not to think about the stretch of Mother’s days, now that we were at school, and she had nothing to soothe. She had spent the morning preparing for Father’s return, her fingers laced with pastry and meat. She had left the pie to cool and fallen asleep on the sofa, amongst her blankets. She woke in the mid-afternoon with the shock of the empty house.

‘Where is he?’ she said.

She had passed by the Lifehouse. The windows were dark.

‘Let’s get the others,’ I said. ‘Let’s get everyone home.’

The school office was decorated for Christmas. Pink tinsel hung around the secretary’s desk, and a plastic tree had been unfolded outside the headmaster’s door. I asked where I could find Ethan, and the secretary informed me that he had been marked absent that morning, and every other morning that week. ‘Aren’t you his sister?’ she asked.

‘I think that there’s been a mix-up,’ I said. ‘He was here this morning. I mean – we walked here. Together.’

‘Well, that’s not what the register says.’

The secretary had a heater beneath her desk, and she rested her bare feet between its gratings. She stared at me, as if she was waiting for me to leave. Through the doors, I could see Mother, huddled against the wind at the edge of the playground. An uncollected child at home time.

‘Thanks, anyway,’ I said.

By the time we returned home, Ethan was waiting for us, impatient and confused. ‘Shouldn’t you be in bed?’ he said to Mother. He listened to the story of Father’s disappearance with ever-widening eyes, and as soon as Mother was finished, he sat at the kitchen table and commandeered the phone. There was nobody at the church in Blackpool. Jolly’s phone rang out. Mother stood over him, trembling, with her fingers at her throat. Delilah called to her from the couch, asking for a hug, and as soon as she was in the other room, Ethan started ringing hospitals.