The television camera was focused on Shannon Carter’s face. Her eyes seemed to stare down the lens and into Catherine’s. It was a pre-recorded interview filmed in a hotel suite somewhere in London, and, as she spoke, Catherine noticed her lipstick had bled into the feathery cracks above her mouth. Her voice had deepened over the years, the flat vowels knocked into shape. She still had a horseshoe-shaped mole on her cheek.

‘There is something that has bothered me for a long time,’ said Shannon, her hands folded in her lap.

‘Can you explain to the viewers what that is?’ The interviewer. Male. Sympathetic. Off camera.

‘My sister. I never got a proper chance to say goodbye to her. To say sorry. For everything that happened. For what I did.’ Her gaze dropped away. An incisor indented her bottom lip. ‘I’ve been able to build a new life for myself. I hope she has too. We both lost our parents that night, and I think everyone forgets that.’

‘If you knew your sister was watching this right now, what would you say to her?’

Shannon lifted her head and spoke directly into the camera. ‘I’m so sorry. I hope you can forgive me. I would love to see you again. I want to know how you are, and what your life is like now. To let you know I still love you and—’

Shannon’s face disappeared and was replaced by a scene in a kitchen. Raised voices. Muted colours. From the glare of studio lights to the depressing environs of Albert Square. Edward had flipped channels again and landed on a soap opera.

Catherine’s legs were trembling. She leaned back into the armchair to gather herself. Edward was no longer lolling on the sofa, but sitting up straighter, an expression of puzzlement on his face. Honor looked up from her mobile phone with mild interest.

‘Can you imagine,’ she said, ‘what it would be like to have a sister who stabbed your parents to death?’

‘Might be a bit awkward at Christmas.’ Edward chuckled to himself, his earlier bemusement vanishing into mirth. He switched channels again.

Catherine’s tongue was so dry it had stuck to the roof of her mouth. Her legs had stopped shaking, but she felt scooped out inside, as if someone had forced a hand into her chest and pulled out her heart.

On autopilot, she released an obligatory huff of laughter at Edward’s weak joke and stared at the television, but had no sense of what she was watching. Catherine’s gaze went beyond the screen and to the blood-spattered walls of her childhood.

Can you imagine what it would be like to have a sister who stabbed your parents to death?

Honor’s tone had been laced with incredulity, fascination even. And something thicker and darker. Repulsion.