She leaned away and slashed the scalpel across my chest. Compared to the pain in my eye, it was a scratch. I wanted to scream at her. Tell her to do her worst. I wanted to die, but more than that: I wanted her dead. I conjured up every bit of strength I had left and bucked and thrashed and struggled, but whatever she had given me meant I hardly moved, and she laughed.

She brought the blade back towards my eye.

The front door opened with a rattle and click.

Rachel sat up, looking at her watch, as if she had been expecting someone, but not so soon. I realised I had been holding my breath, and exhaled through my nose, relief flooding through me. Rachel dismounted me and picked up the butcher’s knife from the bedside table where she’d left it, moving slowly, careful not to make a noise. I shouted into the gag.

A voice called out. ‘Hello?’

It was Charlie.

I tried harder to shout, to warn her. But all I could do was turn my head and watch with my remaining good eye – Oh God, I was blind in one eye – as she came into the room. As she took in the scene – Rachel with the knife, me naked and bloody on the bed – her mouth fell open and she tried to back out of the room. But Rachel grabbed her by the arm with her free hand, pulling Charlie and throwing her across the room. She crashed into the chest of drawers and fell to her knees.

‘What have you done to him?’ she screamed, eyeing the knife and staying where she was.

Rachel panted, ignoring the question. ‘How did you get here so quickly?’

I guessed from this question that Rachel had been expecting Charlie. No doubt Rachel was planning to kill her too, but she wanted me blind and helpless first, so I would have to listen to my girlfriend – if she was still my girlfriend – die. Charlie was the one Rachel hated the most. Because she was the woman I really loved.

Charlie climbed to her feet. Through the tears pooling in my right eye, everything was blurred, colours and shapes swimming in the bright light.

‘How did you get here?’ Rachel demanded, jabbing the knife towards her.

A male voice said, ‘I gave her a ride.’

I turned my head. Rachel turned too. It was Henry. Huge, muscular, strong, tall Henry. Come to save us. Oh thank God, thank God. He stepped towards Rachel with his hand outstretched, a towering presence, his motorbike boots thumping on the floor. He opened his mouth and said, ‘Give me—’

Rachel plunged the knife into his chest.

I watched in stunned horror – everything in slow motion – as our apparent saviour slumped to the floor, hitting the ground with a thump.