She eventually discovered that the swarm was very, very old – and not alone. There were others scattered through distant galaxies, having seeded themselves across the face of the universe over vast epochs of time. The origins of this particular swarm dated back to a time when the Earth’s sun had barely coalesced from interstellar dust.

It was clear that these swarms maintained contact with each other, despite the vast distances that separated them, by some means Dakota did not yet understand. Although tach-net communications were instantaneous, the amount of energy required to boost a signal so enormously far staggered the imagination. How the swarm obtained the requisite energy was a question that, at least for the moment, might have to remain unanswered.

Mos Hadroch. The term turned up again and again, and it soon became clear that, whatever it might be, the swarm regarded it as a major threat to its primary mission, even while its precise nature remained frustratingly elusive.

‘We’re getting nowhere in trying to work out what the Mos Hadroch is,’ said Dakota. ‘I’m going to get in contact with the other navigators back home, see if they can help.’

She was standing with Josef’s ghost on the roof of a kilometres-high structure on an otherwise deserted world drawn from the ship’s memory. A real-time image of the red giant hung above them, great loops of fiery plasma torn from its surface outlining the flux of its magnetic fields.

He looked at her with a doubtful expression. ‘What could they possibly do? For all we know, the Mos Hadroch might be somewhere back in the Greater Magellanic Cloud – or might not even exist anymore. Maybe we should be trying to think of something new.’

‘No, you don’t understand. The Shoal abandoned a coreship before they left our part of the galaxy. What if there’s some clue buried in its data stacks? Or in the wreck of the godkiller back in Ocean’s Deep? There are navigators back home who’ve been flying their own Magi starships for a couple of years now. If I send them everything we know, they might find a correlation within minutes.’

I’m talking to myself, Dakota thought, as she studied the ghost. That’s all he is: another part of me that thinks it’s someone else. More evidence, if it were needed, that her mind was now unravelling.

‘The risk of making contact with home is enormous, Dakota. It’s suicidally risky.’

‘How do you mean?’

The ghost turned towards her. ‘Think about the energy cost of transmitting a signal across seventeen thousand light-years, all the way back to Ocean’s Deep. Without enough power, it’ll de-cohere into random noise before it even gets there. You’re going to have to drain the drive’s energy reserves to make sure they receive the message.’

‘So?’