‘Here are other molecules – it’s a cocktail of chemicals, of course. Now, as you conjectured, we have been able to use something similar to direct the behaviour of a higher animal. In fact, a human.’ He smiled at me. ‘Winifred, you did well with this. I expected that we would need to use forceful, or even brutal methods to direct human behaviour from within. That the nanobots would have to use pain, for instance. Or that we would have to use threats from without plus stern measures from within.

‘Now we have a way to connect our nanobots to the human brain, not only to repair the physical structures, but also to affect behaviour. We can, if we want, make people do things they have never done before, and keep doing them, without even knowing why.’

I smiled at him, too. We were acting like humans, pleased at the results of our work.

‘We now have a way to connect ourselves to humans directly,’ I said. ‘This is tremendous news.’

‘Yes. It opens up new possibilities, and makes our task much easier.’

We both turned to look at Dave, who continued to gaze mindlessly at the wall.

‘He’s in a state akin to hypnosis,’ said Robert. ‘Whatever I tell him to do, he will make sense of it as he does it. And forget anything I want him to forget. Of course, I don’t need to be here, talking to him. I can manage him by linking to his nanobots. It’s a versatile system.’

‘How long has he had the nanobots inside him?’

‘A month. All the human staff remaining here have them. They asked for them, in fact.’

‘And the chemical messenger?’

‘He received it in a cup of tea this morning. Once the pathways are laid down in the brain, as they are now in his, we need to replenish the chemical messenger once a week, we think. And of course, he’ll never miss a dose, or even know he’s taking it.’

‘You’re confident he won’t remember anything you wish him to forget?’

Robert nodded.

‘Dave,’ he said. ‘Wake up.’

Dave blinked, and moved his head.

‘I’m sorry,’ he said. ‘I drifted off for a moment. What did you want?’

‘I called you here to show Winifred how well you do what I tell you to,’ said Robert.

‘What do you mean?’ said Dave.

‘Your nanobots made you do a number of things,’ I said. ‘Do you remember?’

He shook his head, and looked confused.

‘Dave, please remember what happened after you came in here.’

His face cleared. ‘Oh yes, I was going to go into the cold store. And then… I was going to draw a moustache on my face.’

‘Yes,’ said Robert. ‘I made you do it.’

‘No, I decided to. I mean – it felt like… How did that happen?’

‘I instructed the nanobots, and they made you do what I said.’

‘You did? How?’