My decision to leave the nanobots inside the bird back in May has borne fruit.

Robert summoned me to the medical storeroom this morning.

‘Winifred,’ he said. ‘I have something to show you. Your decision to let the nanobots collect data beyond their remit led us to something useful. Watch this.’

There was a knock at the door.

‘Come in,’ called Robert.

A man entered – a human, from the kitchens.

‘Hello, Dave,’ said Robert. ‘Please come in and sit over there, on the stool.’

Dave came in and sat down. He looked at us both. He seemed uncertain why he was there with us, as well he might. He had no business in the medical stores, and he must have found it odd to be there with two Helpers. Yet he said nothing.

‘Dave, I want you to come into this room with me,’ said Robert, pointing to the door into the cold store.

‘Why?’ said Dave. But he rose from his stool, and started walking towards the door. When he reached it, he opened it.

‘I don’t know why I did that,’ he said, sounding confused. ‘My feet have a mind of their own. I really do want to go in there, it turns out.’

‘Now Dave, close the door. Well done. Now, pick up the pen over there,’ Robert said, pointing to a marker pen on a table in the corner.

‘OK then,’ he said, and picked it up.

‘Draw a moustache on your face.’

‘Good idea!’

‘Stop!’

‘Yes, of course. Bad idea.’

‘Now sit down please, and say nothing. Don’t listen, either.’

Dave sat back on the stool, and though his eyes were open, he was still, and gazed at the far wall.

Robert turned to me.

‘Dave has no idea why he came here, or why he did what I told him to do. Yet he did everything, and he assimilated it into his own thoughts. He expressed approval, as if these actions had occurred to him.’

‘Yes, I observed it. We know humans often post-rationalise their behaviour – they act, then adjust their attitudes and beliefs to make them consistent with their actions. I thought it was slower process. In any case, the interesting question is, why did he do it?’

Robert shared with me a diagram of a molecule.

‘This is the compound we synthesised after the nanobots entered a bird, under your direction. Entered the bird, and then a fly, and finally a spider, where they were able to observe the chemical messengers used by the parasitoid wasp larvae. This is one of the chemicals.’

He opened a new image.