Catherine considered telling the truth, could taste it rising from a place within. But she had kept it to herself for so long, parcelled up and put away, that she didn’t know how to remove all the layers of deceit and painful history, suspecting that even if she did proffer up the gift of her innocence, it would be cast out.

She was ten when she confessed to killing her parents. A vulnerable and naive young girl. She had not understood the repercussions of the lie she had told. Only that, in the absence of loving role models, she had worshipped her sister with an intensity that meant she’d sacrificed herself at the altar of law to protect her. Put simply, it had felt like the right – the only – thing to do.

With the benefit of perspective – of adulthood and becoming a mother herself – she recognized that Shannon’s failure to speak up had been selfish. Worse than selfish. Destructive.

Like Catherine, her sister had been a victim too. But if Shannon’s conscience had not led her to confess, she should, at the very least, have tried to make reparation of some kind. Instead Shannon had stopped writing to her twenty years ago, eighteen months after Catherine had moved into the unit. When she was released and given a new identity, Catherine’s last tie to her sister had been cut. The betrayal still stung, but she had learned to live with it.

Was that why Shannon was now seeking forgiveness in the most public of ways? Not for financial gain, but because she was genuinely sorry and wanted to be certain that her sister knew it all these years later. Perhaps she wanted to reconcile and make amends at last.

Even after everything, Catherine was still making excuses for her.

The doorbell rang, intrusive in the shock of the night. Edward glanced down the stairs, frowning. Honor stilled, eyes widening like a frightened rabbit.

Someone opened the letter box. ‘Sara Carter?’ A shout, tinged with antagonism. Killers didn’t deserve sympathy, did they? ‘Open the door. We know you’re in there. Just give us a quote – something we can use – and we’ll leave you alone.’

Sara Carter.

All at once, she couldn’t breathe, her past polluting the air like a toxic gas. The telephone was ringing too, a shrill call to action from her bedroom. She hesitated, afraid it might be another journalist, before relenting and running along the landing to answer it, in case it was important. Edward had sprung to life and was helping Honor pull a jumper over her pyjamas.

‘Hel-lo?’ She despised herself for the way her greeting cracked apart in the middle.

‘Catherine Allen?’