“Honestly? I don’t know. It wasn’t my confession to make. And Mum obviously didn’t want us to know or she’d have told us herself. And can you really blame her? Think what could have happened if anyone had found out.”

“What’s that got to do with you telling me? What do you think I’d have done if I’d known? Gone to the police? For God’s sake, Lily, don’t you credit me with any integrity at all? I’ve never told anyone what I thought you’d done. I’d have never put Mum in jeopardy like that.”

“I’m not saying you would. I’m just saying it wasn’t my story to tell.”

They both fell silent. Lily thought about her mum in Central Park, wondering where she was, whether she was back at the hotel yet, feeling a stab of panic that she shouldn’t have left her alone.

“Did you never tell anyone? Not even Daniel?”

Lily shook her head and looked down at the table, noticing how the grain of the wood rippled across its surface. There had been so many moments when she’d considered confiding in Daniel, but each time the fear of exposing her mum had stopped her. Now Lily wondered whether it had always been there in her marriage, wedged between them, whether any relationship could survive a secret like that.

Lily thought back to that morning in the school toilets—less than half an hour after watching her mum give Zoe the overdose—grieving for a death she wasn’t yet supposed to know had happened. A death she had been convinced was all her fault. She had not known then that she would spend the next three decades striving for perfection as a means of smothering her guilt. She had not known that she would study with a feverish commitment to get the A-level grades needed for Oxford, or that throughout her three years at university she would make no lasting friendships, allow herself no romantic encounters. She had not known that she would immerse herself in her studies as a distraction from her thoughts, a tactic she would employ for many years to come, professional approbation filling the gaping void where her family should have been. She had presented a picture to the world of a life and a career so unblemished there had been days she had almost managed to believe it herself.

In lieu of anyone to confide in, Lily had shed the events of that summer like a snake shedding its skin, refashioning herself into someone new, someone good, someone other people aspired to be. It was an impression of her life she had clung to as tightly as if it were a raft in the middle of an ocean. But the fear had always been there, sitting on her shoulder like a vexatious golem: the fear that at any moment the truth might be discovered. Countless times over the years she had imagined her mum confessing, imagined the police interviews, the trial, the prison sentence. So many times she had tried to imagine what she would say if questioned, whether she would confess to her part in it, whether she would acknowledge that she had sown the seed in her mum’s mind. But this was one part of the scenario where her imagination always failed her.