Luke never talked about his older sister and Clara only knew the bare facts: when she was eighteen, Emily had walked out of the family home and was never heard from again. He’d been ten years old at the time, his brother Tom, fifteen. He had told her a few months after they’d started dating, one night at his old place in Peckham, a shared flat off Queens Road in a dilapidated Victorian terrace, where at night they would lie in bed and listen to the music and voices carrying from the bars and restaurants squeezed into the railway arches across the street, trains thundering over the elevated tracks above.

‘And you’ve no idea what happened to her?’ she’d asked, astonished by his story.

Luke had shrugged, and when he’d spoken again there was a heaviness to his voice she’d not heard before. ‘No, none of us had a clue. She just walked out one day. Left a note saying she was leaving home, and we never heard from her again. It totally destroyed my family; my parents never got over it. Mum had a nervous breakdown and in the end it was better to never mention her. All the pictures of her got put away, everyone stopped talking about her.’

Clara had sat up, appalled. ‘But that’s awful! You were only ten, you must have wanted to talk about her, it must have devastated you and your brother too.’

The hand that had been stroking her leg paused. ‘We learnt it was better not to, I suppose.’

‘But … was there … I mean, weren’t the police involved?’

He shook his head. ‘She went of her own free will. I think that was the hardest part for my mum and dad – she left a note saying she was going, but no explanation as to why or where. My dad told me they hired a private detective to try and find her but it didn’t come to anything.’ He shrugged. ‘She completely vanished.’

And in that moment she’d understood something about Luke that had always puzzled her. Something she’d glimpsed hovering behind the laughter and the jokes, his need to be the life and soul of every party, a sorrow flickering barely there at the edges of him she hadn’t quite been able to put her finger on before.

‘What was she like?’ she’d asked softly.