He turned to face Sejanus. 'These are some of my brothers, but where are the others? Where am I?'

'I do not know,' replied Sejanus. 'I have walked this place many times, but have never yet seen your likeness.'

'I am his chosen regent!' cried Horus. 'I fought on a thousand battlefields for him. The blood of my warriors is on his hands, and he ignores me like I don't exist?'

'The Emperor has forsaken you, Warmaster,' urged Sejanus. 'Soon he will turn his back on his people to win his place amongst the gods. He cares only for himself and his power and glory. We were all deceived. We have no place in his grand scheme, and when the time comes, he will spurn us all and ascend to godhood. While we were fighting war after war in his name, he was secretly building his power in the warp.'

The droning chant of the official - a priest, realised Horus - continued as the pilgrims maintained the slow procession around their god, and Sejanus's words hammered against his skull.

'This can't be true,' whispered Horus.

'What does a being of the Emperor's magnitude do after he has conquered the galaxy? What is left for him but godhood? What use has he for those whom he leaves behind?'

'No!' shouted Horus, stepping from the plinth and smashing the droning priest to the ground. The augmented preacher hybrid was torn from the pulpit and lay screaming in a pool of blood and oil. His cries were carried across the plaza by the trumpets of the floating infants, though none of the crowd seemed inclined to help him.

Horus set off into the crowded plaza in a blind fury, leaving Sejanus behind on the plinth of statues. Once again, the crowd parted before his headlong dash, as unresponsive to his leaving as they had been to his arrival. Within moments he reached the edge of the plaza and made his way down the nearest of the arterial boulevards. People filled the street, but they ignored him as he pushed his way through them, each face turned in rapture to an image of the Emperor.

Without Sejanus beside him, Horus realised that he was completely alone. He heard the howl of a distant wolf, its cry once again sounding as though it called out to him. He stopped in the centre of a crowded street, listening for the wolf howl again, but it was silenced as suddenly as it had come.

The crowds flowed around him as he listened, and Horus saw that once again, no one paid him the slightest bit of attention. Not since Horus had parted from his father and brothers had he felt so isolated. Suddenly he felt the pain of being confronted with the scale of his own vanity and pride as he realised how much he thrived on the adoration of those around him.

On every face, he saw the same blind devotion as he had witnessed in those that circled the statues, a beloved reverence for a man he called father. Didn't these people realise the victories that had won their freedom had been won with Horus's blood?

It should be Horus's statue surrounded by his brother primarchs, not the Emperor's!

Horus seized the nearest devotee and shook him violently by the shoulders, shouting, 'He is not a god! He is not a god!'

The pilgrim's neck snapped with an audible crack and Horus felt the bones of the man's shoulders splinter beneath his iron grip. Horrified, he dropped the dead man and ran deeper into the labyrinth of the shrine world, taking turns at random, as he sought to lose himself in its crowded streets.

Each fevered change of direction took him along thronged avenues of worshippers and marvels dedicated to the glory of the God-Emperor: thoroughfares where every cobblestone was inscribed with prayer, kilometre high ossuaries of gold plated bones, and forests of marble columns, with unnumbered saints depicted upon them.

Random demagogues roamed the streets, one fanatically mortifying his flesh with prayer whips while another held up two squares of orange cloth by the corners and screamed that he would not wear them. Horus could make no sense of any of it.

Vast prayer ships drifted over this part of the shrine city, monstrously bloated zeppelins with sweeping brass sails and enormous prop-driven motors. Long prayer banners hung from their fat silver hulls, and hymns blared from hanging loudspeakers shaped like ebony skulls.

Horus passed a great mausoleum where flocks of ivory-skinned angels with brass-feathered wings flew from dark archways and descended into the crowds gathered in front of the building. The solemn angels swooped over the wailing masses, occasionally gathering to pluck some ecstatic soul from the pilgrims, and cries of adoration and praise followed each supplicant as he was carried through the dread portals of the mausoleum.

Horus saw death venerated in the coloured glass of every window, celebrated in the carvings on every door, and revered in the funereal dirges that echoed from the trumpets of winged children who giggled as they circled like birds of prey. Flapping banners of bone clattered, and the wind whistled through the eye sockets of skulls set into shrine caskets on bronze poles. Morbidity hung like a shroud upon this world, and Horus could not reconcile the dark, gothic solemnity of this new religion with the dynamic force of truth, reason and confidence that had driven the Great Crusade into the stars.

High temples and grim shrines passed him in a blur: cenobites and preachers haranguing the pilgrims from every street corner to the peal of doomsayers' bells. Everywhere Horus looked, he saw walls adorned with frescoes, paintings and bas relief works of familiar faces - his brothers and the Emperor himself.

Why was there no representation of Horus?

It was as if he had never existed. He sank to his knees, raising his fists to the sky.

'Father, why have you forsaken me?'

The Vengeful Spirit felt empty to Loken, and he knew it was more than simply the absence of people. The solid, reassuring presence of the Warmaster, so long taken for granted, was achingly absent without him on board. The halls of the ship were emptier, more hollow, as though it were a weapon stripped of its ammunition - once powerful, but now simply inert metal.

Though portions of the ship were still filled with people, huddled in small groups and holding hands around groups of candles, there was an emptiness to the place that left Loken feeling similarly hollowed out.

Each group he passed swarmed around him, the normal respect for an Astartes warrior forgotten in their desperation to know the fate of the Warmaster. Was he dead? Was he alive? Had the Emperor reached out from Terra to save his beloved son?

Loken angrily brushed each group off, pushing through them without answering their questions as he made his way to Archive Chamber Three. He knew Sindermann would be there - he was always there these days - researching and poring over his books like a man possessed. Loken needed answers about the serpent lodge, and he needed them now.

Time was of the essence and he'd already made one stop at the medical deck in order to hand over the anathame to Apothecary Vaddon.

'Be very careful, apothecary,' warned Loken, reverently placing the wooden casket on the steel operating slab between them. 'This is a kinebrach weapon called an anathame. It was forged from a sentient xeno metal and is utterly lethal. I believe it to be the source of the Warmaster's malady. Do what you need to do to find out what happened, but do it quickly.'

Vaddon had nodded, dumbfounded that Loken had returned with something he could actually use. He lifted the anathame by its golden studded pommel and placed it within a spectrographic chamber.

'I can't promise anything, Captain Loken,' said Vaddon, 'but I will do whatever is in my power to find you an answer.'

'That's all I ask, but the sooner the better, and tell no one that you have this weapon.'