The Vermiform washed up around my legs and bound them together. ‘Make haste. Be ready.’

I wasn’t ready at all! The room started shrinking: the ceiling was lowering. It drooped in the middle, sagged down, brushed my head. The corners of the walls and the right angles where they met the ceiling smoothed into curves, making the room an oval. I saw Rayne protecting Cyan with her coal shovel raised, then the walls pressed in and obliterated my view. They came closer and closer, dimming the light.

From the box-bed Rayne must have seen worms hanging down from the ceiling, bulging out from the walls, passing her; closing in and leaving the furniture clear until they tightened around me in a flesh-coloured cocoon.

I struggled but the Vermiform held my legs tight. The meshed worms masked my face. I closed my eyes but I felt them squirming against the lids. They let me take a deep breath, then pressed firmly over my lips. Worms closed tightly around my head, all over my body, seething upon my bare skin. I pushed against its firm surface but had no effect. It was like one great muscle.

I couldn’t move, panicked. I was bundled tight! Hard worms gagged me. My chest was hurting, every muscle between every rib was screaming to exhale. I was light-headed and dizzy. I lost the sensation in my fingers, my arms. The curved muscle under my lungs burned. I held my breath, knowing there was nothing to inhale but worms.

I couldn’t stand it any more. I gulped the stale air back into my mouth and exhaled it all at once. I sucked on the worms and my lungs stayed small, no air to fill them. I started panting tiny breaths. My legs were weak, my whole body felt light. I started blacking out.

The next breath, the worms peeled away and cold fresh air rushed into my lungs. I collapsed to my knees, coughing. The Vermiform extended grotesque tendrils and hauled me upright.

I was standing on the cold Osseous steppe, where the horse people come from. It was twilight and silent; the sky darkening blue with few stars. Around me stretched a flat jadeite plain of featureless grass. A marsh with dwarf willow trees surrounded a shallow river; deep clumps of moss soaking with murky water and haunted by midges. Far on the other side of the river a silhouette line of hazy, scarcely visible hills marked the end of the plain.

In the distance I saw a village of the Equinnes’ black and red corrugated metal barns, looking like plain blocks. Between them was one of their large communal barbecues, a stand on a blackened patch of earth where they roast vegetables. A freezing mist oozed out between the barns to lie low over the grassy tundra.

I couldn’t see any Equinnes, ominously because they spend most of their time outdoors and only sleep in their barns. They’re so friendly they normally race to greet strangers.

The Vermiform had reassembled-she stood a head taller than me. She said, ‘We told Membury and the Equinnes that even when the Gabbleratchet vanishes they must not come out for a few hours.’

‘Where is it now?’ I asked. The Vermiform pointed up to the sky above the hills. I strained to make out a faint grey fleck, moving under the stars at great speed. It turned and seemed to lengthen into a column. I gasped, seeing creatures chasing wildly through the air, weaving around each other.

‘It has already seen us,’ the Vermiform chorused. Worms began to slough off her randomly and burrow into the grass. ‘When I say run, run. It won’t be able to stop. Don’t run too soon or it will change course. Be swift. Nothing survives it. If it catches you we won’t find one drop of blood left. Beware, it also draws people in.’

‘What do you mean?’

‘Don’t look at it for too long. It will mesmerise you.’

It was an indistinguishable, broiling crowd, a long train of specks racing along, weaving stitches in and out of the sky. Their movement was absolutely chaotic. They vanished, reappeared a few kilometres on, for the length of three hundred or so metres, and vanished again. I blinked, thinking my eyes were tricking me.

‘It is Shifting between here and some other world,’ said the Vermiform, whose lower worms were increasingly questing about in the grass.

The hunt turned towards us in a curve; its trail receded into the distance. Closer, at its fore, individual dots resolved as jet-black horses and hounds. The horses were larger than the greatest destriers and between, around, in front of their flying hooves ran hounds bigger than wolves. Black manes and tails streamed and tattered, unnaturally long. The dogs’ eyes burned, reflecting starlight, the horses’ coats shone. There were countless animals-or what looked like animals-acting as one being, possessed of only one sense: to kill. Hooves scraped the air, claws raked as they flew. They reared like the froth on a wave, and behind them the arc of identical horses and hounds stretched in their wake.

They were shrieking like a myriad newborn babies. Dulled by distance it sounded almost plaintive. Closer, their size grew, their screaming swelled. As I stared at them, they changed. Yellow-white flickers showed here and there in the tight pack. All at different rates but quickly, their hides were rotting and peeling away. Some were already skeletons, empty ribs and bone legs. The hounds’ slobbering mouths decayed to black void maws and sharp teeth curving back to the ears. Above them, the horses transformed between articulated skeletons and full-fleshed beasts. Their skulls nodded on vertebral columns as they ran. Closer, their high, empty eyesockets drew me in. As I watched, the skeleton rebuilt to a stallion-rotten white eyes; glazed recently dead eyes; aware and living eyes rolled to focus on us.

The horse’s flanks dulled and festered; strips dropped off its forelegs and vanished. Bones galloped, then sinews appeared binding them, muscle plumped, veins sprang forth, branching over them. Skin regrew; it was whole again, red-stained hooves gleaming. The hounds’ tongues lolled, their ears flapped as they rushed through hissing displaced air. All cycled randomly from flesh to bone. Tails lashed like whips, the wind whistled through their rib cages, claws flexed on paw bones like dice. Then fur patched them over and the loose skin under their bellies again rippled in the slipstream. Horses’ tails billowed. Their skulls’ empty gaps between front and back teeth turned blindly in the air. The Gabbleratchet charged headlong.

I shouted, ‘They’re rotting into skeletons and back!’

‘We said they’re not stable in time!’

‘Fucking-what are they? What are they doing?’

‘We wish we knew.’ The Vermiform sank down into the ground until just her head was visible, like a toadstool, and then only the top half of her head, her eyes turned up to the sky. Her worms were grubbing between the icy soil grains and leaving me. They kept talking, but their voices were fewer, so faint I could scarcely hear. ‘The Gabbleratchet was old before the first brick was laid in Epsilon, or Vista or even Hacilith; aeons ago when Rhydanne were human and Awian precursors could fly-’

‘Stop! Please! I don’t understand! You’ve seen it before, haven’t you?’

‘Our first glimpse of the Gabbleratchet was as long before the dawn of life on your world as the dawn of life on your world is before the present moment.’

Never dying, never tiring, gorged with bloodlust, chasing day and night. The Gabbleratchet surged on, faster than anything I had ever seen. ‘How do you think I can outrun that?’

‘You can’t. But you are more nimble; you must outmanoeuvre it.’

I saw Cyan on one of the leading horses! She rode its broad back, decaying ribs. Her blonde hair tussled. Her fingers clutched the prongs of its vertebrae, her arms stiff. She looked sick and worn with terror and exhilaration. I tried to focus on her horse; its withers were straps of dark pink muscle and its globe eyes set tight in pitted flesh. The hounds jumped and jostled each other running around its plunging hooves.