The Horus Heresy: Vengeful Spirit

The cave corkscrewed into the mountain for perhaps a hundred metres, lousy with distorted echoes and strangely reflected light. As tall as a processional on a starship, the passage shimmered with rainwater seeping through microscopic cracks in the rock. The shifting beams caught falling droplets and shimmering rainbows arced between the walls.

They paused as the low, wet growl of something large and hungry was carried from deeper in the tunnels. Territorial threat noise.

‘Whatever that is, we should leave it alone,’ said Kibre.

‘For once I’m in total agreement with you, Falkus,’ said Noctua.

‘No,’ said Horus. ‘We go on.’

‘I knew you were going to say that,’ said Abaddon.

‘And if we run into whatever that is?’ asked Aximand.

‘We kill it.’

The Mournival drew closer to Horus, each with a bladed weapon and firearm drawn. Moisture drizzled the air. It pattered on armour plates and hissed on powered blade edges.

‘You know what it is, don’t you?’ said Aximand.

‘No,’ said Horus. ‘I don’t.’

The sounds of animal breath rasping over dripping fangs came again. It drew Horus on even as some primal part of his brain told him that whatever lurked in the darkness beneath the mountain was something not even he could defeat.

The thought was so alien that he stopped in his tracks.

The intrusion to his psyche was so subtle that only a thought so incongruous to his self-image revealed its presence. It didn’t feel like an attack though, more an innate property of the cave.

Or a side effect of whatever had happened here.

Horus pressed on, the passageway eventually widening into a rugged cavern thick with dripping stalactites and blade-like stalagmites. Some ran together in oddly conjoined columns, wet and glistening like malformed bones or mutant sinews.

A stagnant lake filled the centre of the cavern, its surface a basalt mirror. Rotted vegetation, festering dung and heaps of bone taller than a man were heaped at the water’s edge. The ambient temperature dropped by several degrees, and plumes of breath feathered before the Warmaster and his sons.

Horus’s skin tingled at the presence of something achingly familiar yet wholly unknown. He’d felt something similar at the base of the lightning-struck tower, but this was different. Stronger. More intense. As though his father were standing just out of sight, hidden in the depths and watching. Shadows stretched and slithered as the beams of the Justaerin’s lamps swept around the chamber.

‘I have been here before,’ he said, removing his helmet and hooking it to his belt.

‘You remember this cavern?’ said Aximand as the Mournival and Justaerin spread out.

‘No, but every fibre of my body tells me I stood here,’ said Horus, moving through the chamber.

Light refracting through the translucent columns and crystalline growths imparted colour to the walls: bilious green, cancerous purple, bruise yellow. They were standing in the guts of the mountain. Literally. A chamber of digestion. A suitlight played over the lake, holding steady enough for Horus to picture it as a low-hanging moon.

Not Molech’s moon, but Terra’s moon, as though the lake wasn’t a body of water at all, but a window through time. He’d sat with his father on the shores of the Tuz Gölü and skimmed rocks at the image of the moon and for a moment – just a fleeting moment – he could smell its hypersaline waters.

The light moved on and the water was just water. Cold and hostile, but just water.

With a growing sense of purpose, Horus made his way towards the water’s edge. Shadows where no shadows ought to be stretched over the walls, and a thousand muttering voices seemed to rise from the water. He glanced back at the Mournival. Could they hear the voices or see the shadows? He doubted it.

This cave was not entirely of this world, and whatever was keeping it anchored was fraying. Just by being here he was tugging on its loose threads. The image of bones and sinews returned, something organic, the architecture of the mind.

‘That’s what you did here,’ he said, turning on the spot. ‘You cut through the world here and reshaped us, made us forget what we’d seen you do…’

‘Sir?’ said Aximand.

Horus nodded to himself. ‘This is the scab you left behind, father. Something this powerful leaves a mark, and this is it. The bruise you left behind when you shaped your lie.’

The frayed edge pulled a little more. The scab peeled back.

Ghost shapes moved through the cavern, given life by his picking at the wound in the angles of space and time. Each was numinous and smudged, like figures seen through dirty glass. They were indistinct, but Horus knew them all.

He walked among them, smiling as though his brothers were here with him now.

‘The Khan stood here,’ said Horus as the first figure stopped and took a knee on his left. A second figure knelt to his right.

‘The Lion over there.’

Horus felt himself enveloped in light, cocooned by its cold illumination. He’d retraced the steps he’d taken almost a century ago without even knowing it.