'I am the Guardian of the Dragon!' said Semyon.

The sub-hives and manufacturing regions to the northwest of the Magma City lay in ruins. Kilometre-high hab blocks lay scattered across the burning container port like toppled anthills and smashed war engines burned where they had fallen. Bodies littered the ground and tanks lay on their backs or twisted onto their sides without turrets.

With the destruction of their scouting engines, the Titans of Legio Mortis had pulled back, unwilling to advance through such dense terrain and into the teeth of an unknown number of enemy engines.

Instead, they had settled for an intense bombardment from afar, each engine bracing itself with internal gyros and gravitational stabilisers as they locked out their weapon limbs and began to systematically pound the outer habs and work precincts of Koriel Zeth's domain, careful not to damage the forge.

That was to be captured intact.

Princeps Cavalerio withdrew his forces within the walls of the Magma City as the punishing fire brought the thunder of the gods to earth. Fire sheeted from the sky like the end of days, and the planet was lost in a mist of dust and fire and smoke as the city in the shadow of the volcano shuddered with the fury of the bombardment.

Within the walls, hundreds of thousands of refugees packed the thoroughfares, boulevards and sinks of the city. With nowhere to run, the servants of Adept Zeth huddled in terrified misery as the deafening roar of explosions and the seismic shocks of detonations shook the city from the peak of the forge to its void-shielded foundations.

The Knights of Taranis broke two more attacks on the gate, each time without loss, but Preceptor Stator's mount, Fortis Metallum, took a grievous wound to the chest.

Further west, sealed up in his forge between Biblis Patera and Ulysses Patera, Ipluvien Maximal watched as a screaming host, conservatively estimated to be in the region of half a million soldiers, hurled itself at his shielded walls with power mauls and vortex mines.

Servitor-slaved guns sawed through mob after mob of enemy warriors, but such was the force arrayed against them they might as well have ceased firing for all the difference they made.

Ipluvien Maximal greatly feared that the life of his forge could now be measured in hours instead of days.

In the north-eastern reaches of Tharsis, only Mondus Occulum had been spared the ravages of the enemy, though for what purpose, Fabricator Locum Kane could not fathom.

Perhaps Kelbor-Hal thought he might yet lure Kane to his cause, or maybe the Fabricator General did not wish to risk losing the Astartes production facilities for the Warmaster.

Whatever the reason, Kane gave thanks to the Omnissiah as he stood in the howling winds that swirled around the gigantic Tsiolkovsky towers and landing fields of Uranius Patera, watching as squadron after squadron of Imperial Fists Stormbirds descended like a golden flock of avenging angels.

After his dramatic pronouncement, Adept Semyon lowered his arms and moved past Rho-mu 31 to shoo Zouche and Caxton away from the machine. He adjusted the dials and pressed a number of the buttons, though nothing appeared to happen. Looking disappointed, but not entirely surprised, he shrugged.

'What kind of machine is that?' asked Zouche. 'Some kind of conversion beam engine?'

'Pah, it's too complex for the likes of you to comprehend,' snapped Semyon. 'But, for the record, this is my very own gas discharge machine of the perturbation variety, which creates pulsed electrical field excitations and thus measures electro-photonic glow. What the less sophisticated might call auras.'

'These images,' said Dalia. 'That machine created them?'

'It did indeed,' nodded the adept without looking up. 'It did indeed, though it takes a great deal of effort to convince the subjects of the images to willingly submit to the process.'

'And why's that?' asked Zouche.

Semyon pointed to the imprinted shadow on the upright slab. 'You see that? That's all that's left of someone once the device has been activated.'

'It kills them?' asked Dalia, horrified at the number of deaths that must have taken place in this grim laboratory to satisfy Semyon's research.

'It does,' agreed Semyon with a giggle. 'But such things are sometimes necessary to keep the Dragon quiescent.'

'You know where the Dragon is?' demanded Dalia. 'Can you take us to it?'

Semyon laughed, a high-pitched skirling sound of hysteria. 'Take you to it? Doesn't she know it's all around her, that she walks in the throat of the Dragon even now? Ha!'

'This fellow's mad,' declared Zouche. 'Too much time alone has broken his brain.'

'No,' said Dalia with steely conviction. 'This isn't the Dragon. Take us to it. Now!'

Her friends turned at the commanding tone of her voice and even Semyon blinked in surprise. His eyes narrowed and he peered more closely at Dalia, as if seeing her for the first time.

Semyon grinned and nodded, pulling the hood of his robes over the wispy strands of his hair. 'Very well,' he said, all hint of his former mania vanished. 'Follow me and I will show you the Dragon.'

Semyon and his threatening-looking servitor led them from the laboratory, through the darkened passageway at the far end of the chamber, and into a winding series of tunnels. The gloom soon gave way to a soft light that once again seemed to come from the walls.

The walls here were also smooth, but instead of having the look of fused glass, these tunnels appeared to be fashioned from purest silver. With purposeful strides, Semyon led them through the twisting labyrinth of the incredible tunnels, apparently taking turns at random, but refusing to answer any questions as to their route.

Zouche jabbed his elbow into Dalia's side. 'Wherever this takes us, remember what we talked about on the mag-lev,' he cautioned.

'What was that?' asked Caxton.

'Nothing,' said Dalia. 'Just Zouche being paranoid.'

'Paranoid am I?' smiled Zouche. 'Remind me of that when this Dragon's devouring you, Dalia. See how paranoid I am then, eh?'

Eventually, Semyon brought them out onto a wide ledge high up in a glittering cavern of blinding silver that put Dalia in mind of the hollow core of the planet, such was its size. It was the largest internal space any of them had ever seen or could imagine, the uttermost reaches soaring above and below them, and the shimmering walls curving out to either side of them like the largest amphitheatre ever conceived.

'Behold the Dragon!' cried Semyon, moving to stand before a wooden lectern that was incongruous for its very normality. A thick book with a worn leather binding sat atop the lectern, next to a simple quill and inkwell.

Dalia looked out over the vast expanse of silver that was the interior of the cave, half-expecting to see some winged beast launch itself from its lair.

She glanced over at Caxton and Rho-mu 31, who both shrugged, both equally as puzzled as her. Severine shuffled forward to the edge of the jutting promontory they stood on, her eyes with a glazed, faraway look.

'Severine, watch out,' cautioned Zouche, looking over the edge. 'It's a long way down.'

'This place feels… strange,' said Severine, a tremor of disquiet in her voice. 'Do any of the rest of you feel that?'

Dalia saw Severine looking in confusion at the distant walls of the gargantuan cavern, blinking rapidly and shaking her head as though trying to dislodge a troublesome thought.

'If the Dragon is chained somewhere in here, I expect it's bound to feel a little strange,' said Dalia. She squinted at the far off walls, though their unbroken, reflective sheen made it hard to focus properly.