Twenty minutes before what?

Tack supposed Cowl had placed some kind of destructive device inside the citadel, probably atomic, probably powerful enough to vaporize the citadel right down to the bedrock — lunatics always provided that kind of an out. Tack was now standing balanced on two adhesive mines with his harpoon wound back into its launcher, wondering if the wasp-robot would return for him—when Makali slid down the chute and slammed into him.

One mine gave way, spinning off out into the air, but this was enough to absorb Makali’s momentum, so that when they both fell it was down to the ledge below rather than out past it. Scrabbling to gain traction, they sent stray bones spilling down into the sea. Tack dropped his harpoon launcher and tried to bring his carbine to bear, but Makali successfully knocked it aside and stabbed her fingers at his eyes. He ducked, sliding out a leg to drive his boot into her shin. She toppled, but forwards onto him, driving her forehead into his nose. He then hook-punched her in the gut, but she drove down with her prosthetic arms, demonstrating their mechanical strength. He felt his carbine ripped away from him, and through tear-filled eyes saw that his launcher had fallen to lodge itself next to a half-crushed skull. Makali now tried to turn the carbine on him, but her feet slid out from under her, her shoulder thumping against the pillar as she fell towards Tack, shots punching a line of holes through rusting armour beside him. Tack rolled, grabbing up the launcher and firing it in one move. This close, the harpoon punched straight through her, bonding with a flash to the pillar behind. Still she tried to bring the carbine to bear on him. Tack hit fast wind, and let go of the launcher, which wound itself up to her torso, its flat snout crushing into the open wound the harpoon had already made. She shrieked as she was dragged back against the wall, yet managed to fire the carbine again. Tack rolled off the ledge with her shots scoring the air above him. He had no time to turn his fall into a dive—as sharp metallic legs closed around him in mid air.

Running along the shore, Polly looked back up, but, unable to see either Nandru-Wasp or the citadel through the dustfall, she hurried to catch up with Aconite. The dust now fell so thickly it formed conglomerated flakes. Polly glanced over at the water, at the slow roll of the waves humping up the beach, and in the confusion of the moment it took her a second to understand that there was something strange about these waves: they seemed too sluggish and produced little foam; they had the appearance not of sea water waves but of ripples in a thickening soup. Along the strand there now accumulated a mound of gelatinous fragments.

‘What is that?’ She pointed, as she came up beside Aconite, who did not seem in good shape.

‘Hydroscopic,’ Aconite said, pausing to press one hand against her blood-leaking ear.

The meaning of the word flowed easily to Polly from the Muse 184 reference, access to it, she had soon discovered, now so much easier without Nandru in the way. She stooped, picked up a handful of the dust, raised her mask, and spat into the gritty substance. The dust quickly absorbed her saliva; single grains expanding into gelatinous blobs a hundred times their original size.

‘What is it?’ she asked.

‘The basis of Metazoan life—of us, too, eventually,’ Aconite replied, as she set out again.

Soon they reached the estuary and ran along the bank of the river to where the water was shallowest. There they waded across through a thixotropic flow of jelly till they reached the other shore, knocking away blobs of the gelatinous substance clinging to their clothing. As they laboured up the hill, Nandru-Wasp thrummed overhead, bearing its new load.

‘What… what is Cowl going to do?’ Polly gasped.

Aconite did not have the breath to reply. She turned to Polly, then stumbled down on one knee. After Polly helped her up, they struggled on. Then a figure loomed out of the dust storm. Tack didn’t hesitate: he grabbed Aconite and slung her over his shoulder, then turned and ran up towards the house. Polly was struggling to catch up and, reaching the door behind them, she looked back and caught a brief view of the citadel, a glow igniting underneath it—and spreading.

Once inside, Tack put Aconite down on her feet and she staggered over to lean against a table.

‘Shut the door,’ she rasped.

Polly did as instructed, stripping her mask off as she returned. Tack and Aconite removed their masks too.

Aconite turned to Nandru-Wasp, who was squatting amid the detritus of her home. ‘Can you find the generator start-up code?’

‘I should think so,’ Nandru replied.

‘Then start the fucking generators!’

After a pause, a low humming vibration permeated the house.

‘Now turn on the vorpal feed.’

The tone of the hum changed, its pitch climbing in degrees until it escalated beyond human hearing. Polly felt again something of what she had experienced when she had shifted—a reminder of the last horrible stages of her journey into this past, a hint of the tor webwork in her flesh and bones and in the very air around her.

‘That’s the best we can do,’ said Aconite, moving to a sofa and slumping down, to rest her head back and close her eyes.

‘What’s your brother doing?’ Tack asked

With eyes still closed, Aconite said, ‘My brother wanted to start again with a clean slate when he tried to avoid the omission paradox. He wiped out all pre-Nodus life on Earth by distributing a network of molecular catalysing engines across the ocean bottom. They do not destroy themselves like the weapons version, so that network still exists.’

‘Why does that affect us? I don’t understand,’ Polly asked, sure she could now see glowing lines showing through the outer walls of the house.

Aconite’s eyes snapped open. ‘Where can my brother go now? Outside the Nodus the Heliothane will hunt him down. They’ll never give up, no matter how inaccurate their vorpal jumping may be—he’s too dangerous. The only place for him is to get beyond reach down the slope. So he has started those engines and the reaction will kill all nascent life existing in every drop of water on Earth—which would have had no temporal effect before this time. It won’t end that nascent life because the dust will blow from land to sea. But enough of it will be wiped out for long enough, to shove him down to the bottom of the probability slope, where it starts here in the Nodus.’

‘But then what, for him… for Saphothere?’ Tack asked.

‘Maybe there his alternate will slide into oblivion, maybe a new and distinct time-line will develop and create its own slopes. The strength of the paradox he is creating would have dragged us down with him, but here, with the vorpal skeleton of this house carrying a huge temporal charge, we may yet hold.’

‘He’s shooting his father,’ observed Tack.

‘Precisely,’ Aconite replied. She waved towards the window, from which Cowl’s citadel was visible. Polly moved over to it and Tack came up behind her. Through waves of falling dust they saw the citadel shimmering, the glow in the sea underneath it blooming and spreading to the horizon, and felt the tension drawing the air taut, as a whole world tried to fold away. The house now began to quake and Tack wrapped an arm around Polly’s waist. Then suddenly light speared down through the citadel and began turning it into ineffable interspace. The house lurched in response to the turning, then juddered as if hit with a missile; fragments of wall material clattering down. Another violent wrench threw Polly and Tack to the floor, and sent things crashing down throughout the interior of the house.

Then stillness.

Tack helped Polly stand and they moved to the window. Cowl’s citadel was gone, the glowing in the sea was gone. The dust storm was now settling.