Poseidon's Wake by Alastair Reynolds Read Free Book Online

greenbread and paperwork, four square walls and a horizon that stayed still – that was all he really wanted from life.
    Even without the tracking device, it was not usually too hard to find Arethusa. They knew her haunts, her favoured latitudes and familiar places. The only large living thing anywhere in Crucible’s waters, she could be tracked using the ancient and venerable methods of submarine warfare. She gave off a mass signature and distorted the waters above her as she swam. Her songlike ruminations, when she talked to herself or recounted Chinese lullabies, sent an acoustic signature across thousands of kilometres. Networks of floating hydrophones triangulated her position to within what was normally a small volume. During times of heavy weather or seismic activity, though, she had stealth on her side.
    Nonetheless, the merfolk had narrowed down her location, and swimming out from the hydrofoil they had finally sighted their quarry. But that was as close as the merfolk could get. They owed their very existence to Arethusa – she had been involved since the start of the Panspermian Initiative. Some obscure bad blood lay in their mutual past, however, and she would not deign to talk to them any more.
    So Mposi had to swim alone. The merfolk fitted him into a powered swimsuit equipped with a breathing system and launched him into the darkening swell. He gave chase, and of course Arethusa indulged in her usual games, allowing him to come very near before swimming away faster than he could follow. She could keep this up until the cells in his suit ran out of energy.
    But Mposi knew that curiosity would eventually prompt her to relent.
    ‘It’s me,’ he sent into the water ahead of himself, using the suit’s loudspeaker. ‘We need to talk. It’s nothing to do with the tracking device – I’ll never ask such a thing of you again. This is something else, and I need your advice.’
    But it always paid to flatter Arethusa.
    ‘More than your advice,’ Mposi added. ‘Your wisdom. Your perspective on events. No one has your outlook, Arethusa, your breadth of experience or insight.’
    It was hard to talk. The suit was powered, but it still required some effort to drive and coordinate his movements. His lungs burned, even when he turned up the oxygen flow in his mask. She would hear his weakness, he felt sure. She would hear it and mock him for it.
    ‘Something’s happened,’ Mposi carried on after he had swum a dozen more strokes. ‘A signal’s come in from a long way off. We don’t understand why it’s been sent to us, or what we should make of it. There’s a chance it has something to do with—’
    ‘That dolphin-torn, that gong-tormented sea.’
    She had answered, in her fashion, and his suit had picked up the emanations and converted them into natural Swahili. Arethusa did in fact speak Swahili, or at least she had been able to in the past. Lin Wei, the girl she had once been, had attended school in East Equatorial Africa.
    Dolphin-torn, gong-tormented.
    He was doing the one thing he had meant not to do – getting on her nerves.
    But she slowed, allowing him to narrow the distance between them, and he was soon approaching her great fluked tail. His mask showed her body, two hundred metres away, as a whiskered oval. She had been two hundred metres long when she hurt him; now she had grown by a third as much again. Arethusa was the oldest sentient organism, as far as Mposi knew. But the cost of that sentience was an endless need to grow. To grow, and to move further and further from the epicentre of human affairs. The murmurings the hydrophone network picked up were increasingly strange, increasingly suggestive of a mind that had slipped its moorings.
    And yet he would still risk all for an audience.
    ‘The signal,’ Mposi persisted, ‘was aimed at us, unidirectional. Low power, even allowing for the transmission distance – and while it repeated long enough for us to recover the content, it was only