Vargovic knew — beyond any reasonable doubt — that what he was seeing was a Denizen. Others loomed from the cave’s depths — five more of them, all roughly similar, all aglow with faint bioluminescence, all regarding him with darkly intelligent eyes. Vargovic had seen pictures of mermaids in books when he was a child; what he was looking at now were macabre corruptions of those innocent illustrations. These things were the same fusions of human and fish as in those pictures — but every detail had been twisted towards ugliness, and the true horror of it was that the fusion was total; it was not simply that a human torso had been grafted to a fish’s tail, but that the splice had been made — it was obvious — at the genetic level, so that in every aspect of the creature there was something simultaneously and grotesquely piscine. The faces were the worst, bisected by a lipless down-curved slit of a mouth, almost shark-like. There was no nose, not even a pair of nostrils; just an acreage of flat, sallow fish- flesh. The eyes were forward facing; all expression compacted into their dark depths.
The first creature had touched him with one of its arms, which terminated in an obscenely human hand. And then — to compound the horror — it spoke, its voice perfectly clear and calm despite the water.
‘We’ve been expecting you, Vargovic.’
The others behind murmured, echoing the sentiment.
‘What?’
‘So glad you were able to complete your mission.’
Vargovic began to get a grip, shakily. He reached up and dislodged the Denizen’s hand from his shoulder. ‘You aren’t why I’m here,’ he said, forcing authority into his voice, drawing on every last drop of Gilgamesh training to suppress his nerves. ‘I wanted to know about you… that was all—’
‘No,’ the lead Denizen said, opening its mouth to expose an alarming array of teeth. ‘You misunderstand. Coming here was always your mission. You have brought us something we want very much. That was always your purpose.’
‘Brought you something?’ His mind was reeling now.
‘Concealed within you.’ The Denizen nodded: a human gesture that only served to magnify the horror of what it was. ‘The means by which we will strike at the Demarchy; the means by which we will take the ocean.’
He thought of the chips in his hands. ‘I think I understand,’ he said slowly. ‘It was always intended for you, is that what you mean?’
‘Always.’
Then he’d been lied to by his superiors — or they had at least drastically simplified the matter. He filled in the gaps himself, making the necessary mental leaps: evidently Gilgamesh was already in contact with the Denizens — bizarre as it seemed — and the chips of hyperdiamond were meant for the Denizens, not his own people. Presumably — although he couldn’t begin to guess at how this might be possible — the Denizens had the means to examine the shards and fabricate the agent that would unravel the hyperdiamond weave. They’d be acting for Gilgamesh, saving it the bother of actually dirtying its hands in the attack. He could see why this might appeal to Control. But if that was the case… why had Gilgamesh ever faked ignorance about the Denizens? It made no sense. But on the other hand, he could not concoct a better theory to replace it.
‘I have what you want,’ he said, after due consideration. ‘Cholok said removing it would be simple.’
‘Cholok can always be relied upon,’ the Denizen said.
‘You knew — know — her, then?’
‘She made us what we are today.’
‘You hate her, then?’
‘No; we love her.’ The Denizen flashed its shark-like smile again, and it seemed to Vargovic that as its emotional state changed, so did the coloration of its bioluminescence. It was scarlet now, no longer the blue-green hue it had displayed upon its first appearance. ‘She took the abomination that we were and made us something better. We were in pain, once. Always in pain. But Cholok took it away, made us strong. For that they punished her, and then us.’
‘If you hate the Demarchy,’ Vargovic said, ‘why have you waited until now before attacking it?’
‘Because we can’t leave this place,’ one of the other Denizens said, the tone of its voice betraying femininity. ‘The Demarchy hated what Cholok had done to us. She brought our humanity to the fore, made it impossible for them to treat us as animals. We thought they would kill us, rather than risk our existence becoming known to the rest of Circum-Jove. Instead, they banished us here.’
‘They thought we might come in handy,’ said another of the lurking creatures.
Just then, another Denizen entered the cave, having swum in from the sea.
‘Demarchy agents have followed him,’ it said, its coloration blood red, tinged with orange, pulsing lividly. ‘They’ll be here in a minute.’
‘You’ll have to protect me,’ Vargovic said.
‘Of course,’ the lead Denizen said. ‘You’re our saviour.’
Vargovic nodded vigorously, no longer convinced that he could handle the three operatives on his own. Ever since he had arrived in the cave he had felt his energy dwindling, as if he was succumbing to slow poisoning. A thought tugged at the back of his mind, and for a moment he almost paid attention to it; almost considered seriously the possibility that he was being poisoned. But what was going on beyond the cave was too distracting. He watched the three Demarchy agents approach, pulled forward by the tugs they held in front of them. Each agent carried a slender harpoon gun, tipped with a vicious barb.
They didn’t stand a chance.
The Denizens moved too quickly, lancing out from the shadows, cutting through the water. The creatures moved faster than the Demarchy agents, even though they only had their own muscles and anatomy to propel them. But it was more than enough. They had no weapons, either — not even harpoons. But sharpened rocks more than sufficed — that and their teeth.
Vargovic was impressed by their teeth.
Afterwards, the Denizens returned to the cave to join their cousins. They moved more sluggishly now, as if the fury of the fight had drained them. For a few moments they were silent, their bioluminescence curiously subdued.
Slowly, though, Vargovic watched their colour return.
‘It was better that they not kill you,’ the leader said.
‘Damn right,’ Vargovic said. ‘They wouldn’t just have killed me, you know.’ He opened his fists, exposing his palms. ‘They’d have made sure you never got this.’
The Denizens — all of them — looked momentarily towards his open hands, as if there ought to have been something there.
‘I’m not sure you understand,’ the leader said, eventually.
‘Understand what?’
‘The nature of your mission.’
Fighting his fatigue — it was a black slick lapping at his consciousness — Vargovic said, ‘I understand perfectly well. I have the samples of hyperdiamond, in my hands—’
‘That isn’t what we want.’
He didn’t like this, not at all. It was the way the Denizens were slowly creeping closer to him, sidling around him to obstruct his exit from the cave.
‘What then?’
‘You asked why we haven’t attacked them before,’ the leader said, with frightening charm. ‘The answer’s simple: we can’t leave the vent.’
‘You can’t?’
‘Our haemoglobin. It’s not like yours.’ Again that awful shark-like smile — and now he was well aware of what those teeth could do, given the right circumstances. ‘It was tailored to allow us to work here.’
‘Copied from the ventlings?’
‘Adapted, yes. Later it became the means of imprisoning us. The DNA in our bone marrow was manipulated to limit the production of normal haemoglobin; a simple matter of suppressing a few beta-globin genes while retaining the variants that code for ventling haemoglobin. Hydrogen sulphide is poisonous to you, Vargovic. You probably already feel weak. But we can’t survive without it. Oxygen kills us.’
‘You leave the vent…’
