It seemed like years had passed – not months – since that night in Dublin when Corinne had revealed her family secret. Ever since, the secret had consumed Beth. She had googled around, looking for information that might help to tease out the strands of this problem. She became familiar with the terms: consanguinity, endogamy, autosomal recessive disorder, getting lost down rabbit holes bristling with facts about social order and genetics that she didn’t understand and that hurt her brain when she tried to.

A secret that burdensome was hard to keep. Sometimes, when Beth had been in her father’s den in the evenings, the two of them working in silence on their matchstick construction, and her father would momentarily glance up at her from the blueprints and ask was she okay, that shading of concern in his voice made her long to tell him, lay the facts in front of him and have him make sense of them for her.

‘I thought my mother might notice something,’ Beth said now.

‘Your mother?’ Corinne snorted with derision. ‘If anyone would notice it’s your father. Mark sees much more than her.’

Corinne thought Abi was flakey and false. There was a vein of acid running through her impersonation of Abi – the way she swept into a room, both bossy and inattentive. It made Beth feel guilty when she laughed. But for all Corinne’s assertions, Beth knew her mother was astute, her father perceptive. And she had wondered on the eve of their arrival whether they would meet with Corinne’s parents and instantly guess that something wasn’t right about them.

The answer, it turned out, was no – they didn’t see it. All they were concerned about was Beth’s hair.

It had been Corinne’s idea. Sort of. On one of the days, hot, listless, bored, she’d fingered the brightly coloured ends of her own hair and mused about cutting it.

‘Don’t,’ Beth gently urged. ‘It’s nice the way it is.’ Love leaking into her tone.

‘It’s boring. I’m sick of pink.’

Beth had seen photographs of Corinne with her natural hair colour – a glossy, unexceptional brown. She couldn’t imagine her friend without the cloud of bubble-gum hair, the flighty eccentricity of it like a special mark, an anointed sign.

‘Maybe I should cut it all off,’ Corinne suggested.

‘No way!’

‘Why not?’

‘Your parents would kill you for a start.’

‘But that is the point, right?’

She’d seen the confusion in Beth’s face, and it made Corinne laugh.

‘I did it once before, you know. When I was ten. Cut my hair off to this short. Ksk-ksk,’ she made snipping gestures close to her ears, her eyes taking on the familiar gleam of mischief. ‘You should have seen Valentina’s face!’

Beth tried to imagine it but couldn’t.