Claire didn’t hesitate. The weight settled in her hands, throwing off her balance, but she felt better for having it. Stronger.

‘Before you try using it on me,’ Anderson said, ‘please remember that my friend here has a weapon pointed at your head.’

Claire glanced aside, and saw that the guard behind her had drawn his sidearm, and yes – it was pointed at her, steady and calm. He wouldn’t hesitate, she thought.

‘What do you want me to do?’ she asked. But she already knew.

‘I want you to shoot Oliver,’ Anderson said. ‘I want you to prove to me that I can trust you. He looks as if he is recovering faster than the others, and I want you to render him nonthreatening. Then I want you to continue shooting him. Do you understand?’

Claire swallowed hard, and looked at Oliver. He hadn’t raised his head. He looked frail, and unexpectedly old and vulnerable. ‘Why?’

‘Because I need to be certain we can kill them this way,’ Anderson said. ‘The simulations say it will work. I need to prove the theory, and document how long it takes to accomplish it. You wanted to be a scientist, Claire. This is what it takes.’

Oliver looked up. It seemed to take a vast effort, from the shaking of his body, but he raised his head and met her gaze. His eyes weren’t red. They were dark, and human, and afraid.

‘Please,’ he whispered. ‘Please.’

Claire didn’t honestly know what he was asking. She didn’t know what he wanted. But she knew what she had to do. It had to be done fast, and confidently, and above all, it had to be done without hesitation.

She took a deep breath, said, ‘I’m really sorry, but she’s right. I have to do it.’

And then she raised the weapon and held down the trigger.

It seemed to take forever. Oliver was caught in the beam, twitching, eyes wide, mouth open, and the chains rattled against the hasp like chattering teeth … and then, he collapsed. Dead weight. He fell hard, with no attempt to save himself, and hit the concrete limp and lifeless. All the colour that remained had drained from his face, leaving it eerily blue-white; his eyes were open, dark, and blank. His fangs were down, his mouth half-open.

He didn’t move.

‘How can we tell if he’s actually dead?’ Davis asked. He sounded completely unaffected by the whole thing. Claire felt hot, unsteady, numbed into stillness. She couldn’t look away from Oliver’s eyes.

Dr Anderson went to Oliver, knelt down, and used a silver knife from her belt to cut him. No reaction, though his skin still burned and sparked along the edges of the cut.

She stabbed him. Nothing.