Fresh tears began to fall down Jess’s cheeks and as she wiped them away, Lily began to speak.

“I know none of us can ever completely understand what it was like for you. I guess only another set of twins could. But however hard it is to accept, Zoe was going to die whatever Mum did. There’s no changing that fact. And however conflicted you are with Mum right now, ask yourself what you’d have done in her position. What would you do if Mia was sick, if she was in that much pain, and you knew she wasn’t going to get better? Are you honestly telling me, as a mother, that you wouldn’t want to do something to put an end to her suffering, however awful that thing was? Because I’d like to think that, if I could find the courage, I’d do the same for Phoebe.”

Jess tried to imagine how her mum must have felt as she’d sat on Zoe’s bed and given her the overdose. She tried to envisage what must have gone through her mind as she’d filled the syringe, as she’d administered the excess of morphine, as she’d watched her daughter die. She tried to imagine ever having to do that for Mia but her temples throbbed, resisting the image.

She thought back to that day, walking through the front door, knowing instinctively that Zoe was dead and yet hoping that, if only she could stand still long enough, perhaps she could stop time—reverse it, even—so that the future, when it arrived, might be different.

“Do you know what I find hardest? I can’t even remember the last thing I said to Zoe. She was my twin sister and I can’t recall my last words to her.” Jess wiped at her tears, aware of having said something she hadn’t been able to acknowledge to herself all these years.

“I know, Jess. I understand, really I do. But you can’t undo the past. And things with Mum . . . well, they’re different now, aren’t they?”

Jess thought about her mum wandering alone around Central Park, nursing her disappointment that her longed-for trip to New York had gone so horribly wrong on its first day. She pictured the way her shoulder blades now jutted out from her clothes like stunted wings. She remembered her mum lying under the stiff hospital sheets in the ER less than two months before and how, in the split second after she’d swished back the curtain, the panic Jess had felt was not about seeing Mia and Lily in the same room together but about seeing her mum so frail under the harsh strip lighting.

Jess allowed herself to imagine how lonely and isolated her mum must have been all this time, knowing that the only person in whom she had ever confided about Zoe’s death had found her confession so intolerable that he hadn’t been able to live with it.

Pulling at the soggy tissue between her fingers, she knew that a part of her would always wish things could have been different. She would always wish that she had been told about the severity of Zoe’s illness and that she’d known the truth about her death. But most of all Jess wished, very simply, that Zoe had never got ill. And that was a wish, she admitted to herself for the first time, that hadn’t been in anyone’s control: not hers, not her mum’s, not Lily’s or their dad’s. Not the doctors’ or nurses’ who had tried so valiantly to cure Zoe. Jess realized that she had spent all these years being angry with Lily because it was easier to feel anger than it was to feel grief.