All three Blackstones looked at each other, understanding the implications: the man was dead, and probably not of natural causes.

‘Who do you think killed him?’ asked Dad.

Talk about getting to the heart of the matter. Roger focused on Sunadomari, wondering what he was going to say or do next.

Sunadomari looked straight at him.

‘What did you notice about Rafaella Stargonier’s behaviour?’

‘I—’ How could just speaking be so hard? ‘She did something to a Luculentus in Parallaville. He rocked back, and . . . and afterwards, when I talked to him, he had no memory of her.’

Dad’s eyebrow was raised.

‘Sorry,’ Roger added. ‘It’s part of why I was coming here.’

‘Tell me’ - Sunadomari’s voice became a shade deeper - ‘about Drs Helsen and Ranulph.’

‘Sir? Um . . . Helsen is my tutor. I don’t know the other person.’

Sunadomari gestured, and a small holo appeared on his palm, an image of a stocky man.

‘Oh,’ said Roger. ‘He’s a friend of Helsen’s. I’ve seen him at a distance.’

He looked at Dad.

Should I tell all the rest?

After a moment, Dad gave a half smile.

‘I suggest you come clean, son.’

‘There’s—’ Roger rubbed his face. It felt as if he had a dirty secret habit about to be made public. ‘In the past, I . . . Look, I thought I was stressed out. I get weird dreams and . . .’

Mum spoke for the first time since Sunadomari sat down.

‘Let’s stop here. This is my son, Superintendent.’

‘No, Mum, it’s all right. I thought I was hallucinating, that Helsen is a’ - he shrugged - ‘a creature of darkness. But that’s not really what I mean.’

‘Tell us,’ said Sunadomari.

‘Sometimes she’s surrounded by - things. Twists of darkness. Black fragments of, of - nothing. And they twist in odd ways, I mean geometrically odd ways.’

Now Sunadomari was blinking. So it was possible to surprise a Luculentus. The superintendent stared at Dad, eyes widening, then returned his attention to Roger.

‘You thought these were visual hallucinations, is that it?’

Roger wanted to sob with the relief of confession.

‘Yes. No one else sees them. No one.’

Except in my dreams.

He pushed that aside.

‘And Greg Ranulph, Helsen’s friend. Does this darkness surround him too?’

Roger nodded.

‘I’m curious about something,’ Sunadomari continued. ‘Why were you following Rafaella Stargonier?’

‘I . . . she was suspicious. I mean, I was suspicious of her.’

‘But why did you even see her?’

‘She was meeting with Alisha, my friend . . . Oh, shit.’

‘What is it?’

‘It was Dr Helsen that put Alisha in touch with the Luculenta, er, with Rafaella Stargonier.’

The atmosphere was already charged; now it stepped up a notch.

‘Why would she do that?’

‘To get her to talk about Calabi-Yau, about realspace hyperdimensions. That’s why I took Alisha to the Zajinet place, the research institute.’

He bit his lip, and looked at Dad.

‘All right, son.’

But Sunadomari was looking pale, his eyelids flickering as he immersed himself in Skein.

‘There’s no reply from the institute,’ he said. ‘Did you talk to Luculenta Weissmann?’

‘Luculenta? But she had no—’ Roger thought about her intellectual sharpness, the sense of charisma despite her lack of forehead studs or scalp wires. ‘I should have realized.’

‘So you did speak to her?’

‘Yes. But if she’s not answering—’

‘She should always answer. One moment.’ Sunadomari sank deep inside himself, then came back out of it and looked around the room. ‘I’m despatching full forces, but I expect the worst. And that is the quid, Carl, in a quid pro quo.’

Dad inclined his head.

‘We had our suspicions about the institute, Superintendent. You had the Zajinet prisoner, I take it? The one whose ship crashed nearly twenty years ago?’

‘Yes. Clearly you’ll not speak about this outside this room.’

‘Not in this universe, at least.’

‘Touché. So tell me about the darkness.’

Dad twitched.

‘I don’t—’

Mum reached over and held the back of his hand, which was tightening on the arm of his chair.

‘Carl, relax. Whatever it is . . .’ She looked at Sunadomari. ‘What have you done to him?’

‘Not me. Carl, breathe. Just breathe.’

Roger was scared.

‘Dad?’

‘Breathe, Carl,’ said Sunadomari.

After thirty long seconds, Dad’s chest stopped heaving, and his respiration returned to normal. He wiped sweat from his face.

‘I have no idea what happened,’ he said.

Sunadomari regarded him for a moment.

‘Would you like me to tell you? Perhaps it will be a lesson in whom to trust.’

‘I . . . I don’t know.’

‘Think about it. Now, Roger, it’s clear that Alisha’s father enabled you to pass through the scanners in Barleysugar Spiral. He was the only one with relevant access.’

Roger tried to show nothing.

‘What’s this about a dead person?’ Mum, still looking concerned over Dad, spoke up. ‘Is there a connection, Superintendent, between Xavier Spalding and your murdered friend?’

But Dad was breathing easily now.

‘Was your friend,’ he asked, ‘one of the eight Luculenti who died at the same time?’

‘You know of that? Impressive, Carl.’ Sunadomari blinked. ‘In fact no, Daniel died earlier, but it’s likely the same killer or killers did it. Do you have any suspects?’

‘Sorry. My monitoring picked up the news of their deaths, nothing more. Except for a hint they might have been killed through Skein. Is that what happened?’

Dad was treating Sunadomari as an ally. Roger hoped it turned out to be true.

‘Almost certainly.’

‘So this Rafaella Stargonier must now be your prime suspect.’

‘Perhaps.’

‘Roger said she manipulated a Luculentus, causing . . . amnesia.’

‘That’s right.’ Sunadomari looked at Roger. ‘It’s Dr Helsen’s role I find interesting.’

The paleness was returning to Dad’s face.

‘In the light of what we’ve shared,’ Sunadomari went on, ‘is there any data you can give me, of any kind? Additional speculations?’

‘No,’ said Dad. ‘None I can think of.’

‘I believe you.’

‘So—’

‘So I suggest the three of you leave however you can, as fast as possible. I take it there are faster ways offplanet than through Barleysugar Spiral?’

‘In emergency, yes.’

Roger felt as if the room had tipped sideways. They were fleeing to mu-space? After all his indecision about where he belonged, there was suddenly no choice?

Sunadomari was shaking his head.

‘What is it?’ asked Dad.

‘The institute. My people had to break in.’ Sunadomari looked at the floor, then at the Blackstones. ‘Stella Weissmann is dead, killed in the same way as the other Luculenti. And the basement level is destroyed. A tac team has secured the place.’

‘You mean the cell where you kept the Zajinet prisoner?’

‘Difficult circumstances make for difficult—Never mind. Whether we tortured the Zajinet or not, someone certainly did. There’s nothing left of it.’

‘Why were you interrogating the prisoner, Superintendent? There are other ways to learn about mu-space.’

‘We were more interested in realspace’ - with a glance at Roger - ‘and teleportation through the hyperdimensions. Can’t you imagine how useful that would—?’

Sunadomari stopped, held up a hand, then lowered his chin to his chest and closed his eyes. Five seconds later - surely an age for a Luculentus in the full flow of Skein - he looked up, eyes widening.

‘Thank you for your assistance.’

He stood up.

What the hell?

‘You’ve been very helpful, and I keep my promises, both implied and explicit. You’re free to go.’

Dad also stood.

‘Thank you, Superintendent.’ He held out a formal fist. ‘We’ll be gone within ten minutes.’

Sunadomari touched his fist to Dad’s.