For all her hauteur, Mrs Carter was careful to be kind to the girl next door because her mother was dying and her father painted the outside of Hilltop House every spring, and, most importantly, Mrs Carter knew that gossip spread like seeds on the wind. She wouldn’t send her away.

Shannon was already on the ninth step, light-footed and quick, Sara just behind her, when a door opened downstairs. The click of the latch and the rush of wood pushing against carpet made Sara’s stomach fold over and her knees loosen.

‘Shannon?’ Their father’s voice drifted upstairs, pleasant and low.

Shannon’s whole body tensed, like someone had pressed pause on her life. Sara could not stop in time and bumped into the back of her older sister’s knees.

‘Come here, please.’

Sara’s hand groped for Shannon’s. She squeezed it and Shannon squeezed back. Then her sister turned around and made her way back downstairs.

The study door shut again.

Sara sat down on the eighth step, a pain in her stomach. Knowing Shannon was in the study alone with their parents frightened her. But the last time she’d stood up for her sister, she’d received a punishment of her own. Dr Carter liked to hand out punishments. He believed they were character-building.

She wrapped her arms around her knees and waited.

After what felt like a long time, but was about twenty minutes, the study door opened. Shannon flew up the stairs and did not stop. Sara glimpsed a shock of white-blonde hair, the stain of tears on her sister’s cheeks and a crack in her expression that had been levered apart by the cruelty of their father.

Her sister’s bedroom door closed.

Sara hesitated, not sure what to do next. She loved her sister with everything she had, but Shannon did not always welcome spectators to her most degrading lows.

She could hear her mother and father talking and laughing in the kitchen, the clink of mugs and the grind of coffee beans. Not once had they raised their voices, but that was worse. Their controlled viciousness was a thousand times more painful than the bluster of Brinley’s father or the sweep of Mrs Aggarwal’s broom against their ankles after Shannon, hungry as usual, had thieved a chocolate bar from her shop.

After a few seconds of painful indecision, Sara ran up the stairs to her own bedroom, gathered up the half-eaten packet of biscuits and knocked on Shannon’s door.

A muffled voice. ‘Go away.’

‘It’s me,’ she said, and without waiting for Shannon’s reply, let herself in.

Shannon was lying on her bed, her face buried in her pillow. Sara put her hand over her mouth. Her sister’s hair had been hacked off and stuck out at ugly angles. The back of her neck was exposed, the milky white skin as vulnerable as an unbruised heart.