Lark points the needle towards me. ‘Stay away, Amelia. This has nothing to do with you.’

‘Lark, please. We used to be friends, didn’t we?’ Jackson whispers, his voice barely audible.

Lark turns back to him. ‘Never friends, Jackson. I love you. I’ve loved you since the first time you brought me here.’

‘I’m sorry,’ he says.

‘Lark … please … give me the needle.’ I hold out my hand.

‘And then you said it had just been a bit of fun,’ she says, ignoring my request. ‘That we were both wrong, that we both let my mum down.’

‘Sorry.’ He tugs on the chain that’s holding him to the bed, his wrist raw, covered in scabs and sores.

‘Stop. Saying. Sorry,’ she yells. ‘Why the hell are you fucking sorry anyway? Because you led me on, left me consumed with so much love for you? Or sorry you lured me in and left me with so much guilt that I’d betrayed my mum? Guilt and love is a dangerous cocktail, Jackson.

‘Then my mum got ill,’ she continues. ‘And my guilt was like my very own cancer – killing me. But I kept it all inside, until that night I saw you with Rosamund in Scotland.’

‘I know sorry isn’t enough,’ he whispers.

‘No it fucking isn’t. This is your comeuppance, Jackson. Your punishment.’ She walks towards him. Strokes his hair, his cheek. ‘You’re not as handsome as you once were,’ she says. ‘Far too thin – your muscles wasted.’

She kisses his dry, cracked lips. ‘I love you, Jackson,’ she says, and biting down on her bottom lip so it bleeds, she plunges the needle into his flesh.

‘You’re right, it’s heroin,’ she says, as his eyes linger on hers. ‘It will kill you.’

I stare. Do nothing. My mind paralysed.

‘Lark!’ I finally scream, blaming shock for my delayed reaction, rather than a desire to see Jackson six foot under. I grab my phone from my pocket, but she bashes it from my hand. It crashes to the floor.

‘He must pay for what he’s done, Amelia.’ Her voice is calm and low, but tears roll down her face. ‘Can’t you see that?’

‘No, please, Lark. You can’t let him die.’

Her eyes are wide, vacant, I barely know her. This should have been the best moment of my life – finding my sister alive after all this time – but as I look at Jackson, life draining from him, it’s one of the worst.

‘I attacked him that day at Drummondale House,’ Lark says – she’s still clenching the needle, pointing it my way. ‘I saw him with Rosamund; I couldn’t believe he would do that to me. I struck him with a branch across his head. A bit like the one you’re holding now. Put it down, Amelia. Please.’