The train journey from Harwich to Cambridge was complicated, involving two changes. But it was early on a bank holiday, so the trains were at least largely empty. Breakfast was a waxed paper cup of reheated porridge consumed at Ipswich station. The tea she bought to wash it down turned out to be undrinkable.

It wasn’t yet nine o’clock when she reached Cambridge. She reckoned the chances were reasonable of finding Dr Morrisette at home. Without her phone to locate the address, she had to buy a street map of the city before leaving the station. Fortunately, Alford Street proved to be only a short walk away. She set off at a clip.

Dr Morrisette’s home was in a narrow street of small terraced houses. Wada’s guess was that she lived alone, or at any rate was childless. Espersen had described her as a workaholic, so it all fitted.

If she was a serious workaholic, she might already have left for the day, of course. Sure enough, there was no response when Wada tried the knocker. Tracking her down in whatever part of the university she might have gone to wasn’t going to be easy. Wada stood where she was, trying to think how she could set about doing that. It wasn’t clear it would be feasible on a bank holiday.

Then she saw a woman dressed in jogging kit and carrying a bottle of milk approaching along the pavement. She was short, honed and perspiring, her cropped dark hair plastered to her head. Morrisette? Wada could only hope so.

It was Morrisette. As she neared the door of number 44, she slowed and frowned at Wada. ‘Can I help you?’ she asked. There was quite a lot of muscle under her tight top and knee-length leggings. Her face was raw-boned and tanned. In her voice there was some kind of accent: Australian, maybe.

‘Are you Dr Michaela Morrisette?’

‘Yeah.’

‘My name is Wada. It is extremely important I speak with you.’

‘What about?’

‘Emergence.’

Morrisette tensed. ‘Are you from Quartizon?’

‘No.’

‘Well, in that case I probably shouldn’t be talking to you. What did you say your name was?’

‘Wada.’

‘Right, Wada, well, I don’t know what you’re trying to pull by coming here this morning, but—’

‘We have to discuss the situation, Dr Morrisette. There is something terribly wrong.’ Wada took the memory stick out of her pocket. ‘Just look at what is on this. Then I think you will understand.’

‘Have you been in touch with Quartizon?’

‘The stick came to me from a Quartizon employee who told me you would know what was wrong.’

Morrisette put her hands on her hips, with the bottle of milk hooked on one finger, and stared at Wada. Her knotted expression suggested she was thinking. Hard and fast. ‘OK. You can come in. I’ll give you five minutes. Understood?’

Wada nodded. ‘Understood.’