The Salamanders gave chase, whilst the Devastators moved up the stairs behind them. Dak’ir was halfway across the hall with his squad when he felt the tiny pressure of a wire snapping against his greave. He turned, about to shout a warning, when the entire room exploded.

‘Dead end,’ stated Brother Honorious, standing before the towering barricade of heaped grav-cars and mag-trams.

Tsu’gan and Anvil had left the hydroponics farm a smouldering ruin and had advanced into the city. Directed by Brother Argos, they’d passed through myriad avenues in the urban labyrinth until reaching a narrow defile created by tall tenement blocks and overhanging tower-levels. A hundred metres in and they’d rounded a corner only to find it blocked.

‘We’ll burn through it,’ said Tsu’gan, about to order Sergeant Ul’shan’s Devastators forwards. The multi-meltas would soon–

‘Wait…’ said Tsu’gan, surveying the tall buildings reaching over them. ‘Double back, we’ll find another way.’

At the opposite end of the alleyway a huge trans-loader rolled into view, cutting off their exit. Slowly at first, but with growing momentum it rumbled towards the Salamanders.

‘Multi-meltas now! Destroy it!’

Sergeant Ul’shan swung his squad around to face the charging vehicle just as the cultist heavy weapon crews emerged from their hiding places in the tenements above and filled the alleyway with gunfire.

‘Eyes open,’ hissed Captain Kadai.

The Inferno Guard, together with Omkar’s Devastators, were crouched in ready positions spread across the street. The dangers were manifold – every window, every alcove or shadowed corner could contain an enemy.

Kadai’s gaze flicked back to Fugis as the Apothecary hurried, head low, towards a distant gun emplacement. A Stratosan lay slumped next to its sandbagged wall, alive but barely moving. Kadai watched the trooper’s hand flick up for the third time as he signalled for aid.

Something didn’t feel right.

The trooper’s movements were limp, but somehow forced.

Sudden unease creeping into the pit of his stomach, Kadai realised it was a trap.

‘Fugis, stop!’ he yelled into the comm-feed.

‘I’m almost there, captain…’

‘Apothecary, obey my ord–’

The roar of a huge fireball billowing out from the emplacement cut Kadai off. Fugis was lifted off his feet by the blast wave, the slain Stratosans buoyed up with him like broken dolls. Chained detonations ripped up the road, rupturing rockcrete, as an entire section of it broke apart and fell away creating a huge chasm.

Flattened by the immense explosion, Captain Kadai was still struggling to his feet, shaking off the blast disorientation, when he saw Fugis lying on his chest, armour blackened by fire, gripping the edge of the artificial crater made during the explosion. Kadai cried out as the Apothecary lost his hold and slipped down into the gaping black abyss of Cirrion’s underbelly, vanishing from sight.

From the hidden darkness of the city, the depraved cultists swarmed into the night and the shooting began.

Shrugging off the effects of the explosion, Dak’ir saw figures moving through the settling dust and smoke.

One loomed over him. Its mouth was stitched with black wire; blue veins infected its cheeks. Eyes filled with fervour, the cultist drove a pickaxe against the Space Marine’s armour. The puny weapon broke apart on impact.