Idaeus raised his head and locked his gaze with Uriel. 'You picked a hell of a time to start thinking outside the Codex, sergeant.'

'Better late than never, captain.'

Idaeus smiled and nodded. 'We'll have about thirty seconds from the first detonation to get clear. If we're not off the bridge by then, we're dead. I've already called for another Thunderhawk, but it will not arrive before morning at the earliest.'

The captain opened a channel to the remaining Space Marines in his detachment and said, 'All squads, as soon as the assault troops move, I want enough firepower laid down on these bastards to blow apart a Titan. Understood?'

Shouted confirmations greeted Idaeus's order. He reloaded his pistol and motioned for Uriel to join him at the edge of the gun nest.

From the second gun nest, flaring jets of light erupted as the assault squad fired their jump packs.

'NOW!' yelled Idaeus and the Ultramarines fired everything they had. Volley after volley of bolter shells, missiles and lascannon shots decimated the rebel troopers. The swiftness of death was unbelievable. The Space Marines pumped shot after shot into their reeling mass.

It began with a single rebel turning his back and fleeing into the night. An officer shot him dead, but it was already too late. Others began turning and fleeing through the maze of wrecked tanks, their resolve broken in the face of the Emperor's finest.

And then it was over.

Uriel could not recall how long they had fought for, but it must have been many hours. He checked his visor chronometer and was surprised to find it had been less than two. He knelt and counted his ammo: six clips, not good. Risking a glance over the top level of sandbags, their outer surfaces vitrified to glass by the intense heat of repeated laser impacts, Uriel saw the bridge littered with hundreds of corpses.

The tension was palpable, every Space Marine ready to move the instant they heard the first detonation of a krak grenade. Long minutes passed with nothing but the hiss of the vox, the crackle of flames and moans of the dying outside. Everyone in the gun nest flinched as they heard the crack of rapid bolt pistol fire. The shooting continued for several minutes before dying away.

Uriel and Idaeus exchanged worried glances. Both sides were using bolt pistols.

Uriel shook his head sadly. 'They failed.'

'We don't know that,' snapped Idaeus, but Uriel could tell the captain did not believe his own words.

Weak sunlight shone from the carcasses of the crashed Thunderhawk and smashed tanks on the bridge, their black shells smouldering fitfully. The rain had continued throughout the night. Thankfully, the rebels' attacks had not. There was no detonation of krak grenades and Idaeus was forced to admit that the assault squad had been thwarted in their mission.

Uriel scanned the skies to their rear, watching for another Thunderhawk or perhaps Lightning strike craft of the Imperial Navy. Either would be a welcome sight just now, but the skies remained empty.

A sudden shout from one of the forward observers roused Uriel from his melancholy thoughts and he swiftly took his position next to Idaeus.

He saw movement through the burnt out shell of the Thunderhawk, flashes of blue and gold and heard a throaty grinding noise. The sound of heavy vehicles crushing bone and armour beneath their iron tracks. Darting figures, also in blue and gold, slipped through the wrecks, their movements furtive.

With a roar of primal ferocity that spoke of millennia of hate, the Night Lords Chaos Space Marines finally revealed themselves. Battering through the wreckage came five ornately carved Rhino armoured personnel carriers, coruscating azure flames writhing within their flanks. Uriel was speechless.

They resembled Rhinos in name only. Bloody spikes festooned every surface and leering gargoyles thrashed across the undulating armour, gibbering eldritch incantations that made Uriel's skin crawl.

But the supreme horror was mounted on the tanks' frontal sections.

The still-living bodies of the Ultramarine assault squad were crucified on crude iron crosses bolted to the hulls. Their armour had been torn off, their ribcages sawn open then spread wide like obscene angels' wings. Glistening ropes of entrails hung from their opened bellies and they wept blood from blackened, empty eye sockets and tongue-less mouths. That they could still be alive was impossible, yet Uriel could see their hearts still beat with life, could see the abject horror of pain in their contorted features.

The Rhinos continued forwards, closely followed by gigantic figures in midnight blue power armour. Their armour was edged in bronze and their helmets moulded into daemonic visages with blood streaked horns. Red winged skull icons pulsed with unnatural life on their shoulder plates.

Idaeus was the first to overcome his shock, lifting his bolter and pumping shots into the advancing Night Lords.

'Kill them!' he bellowed. 'Kill them all!'

Uriel shook his head, throwing off the spell of horror the spectacle of the mutilated Ultramarines had placed upon him and he levelled his pistol. Two missiles and a lascannon shot punched towards the Night Lords. Uriel prayed the tortured souls crucified on the Rhinos would forgive them, as two of the tanks exploded, veering off and crashing into the side of the bridge. The prisoners burned in the flames of their destruction and Uriel could feel his fury rising to a level where all he could feel was the urge to kill.

The Space Marine next to Uriel fell, a bolter shell detonating within his chest cavity. He collapsed without a sound, and Uriel swept up his boltgun, emptying the magazine into the traitor legionnaires. A handful of Night Lords were dead, but the rest were closing the gap rapidly. Two more Rhinos died in fiery blasts. Disciplined volleys of bolter and lascannon fire from the Ultramarines in the bunker kept hammering the ranks of Night Lords as they attempted to overrun the gun nests. But few were falling and it was only a matter of time until the traitors reached them.

The Space Marines across the bridge from Uriel and Idaeus perished in a searing ball of white-hot fire as Night Lord warriors unloaded plasma guns through the firing slit of their gun nest. The backblast of the resultant explosion mushroomed into the dawn, incinerating the killers. Still they came on.

Uriel yelled in fury, killing and killing.

An armoured gauntlet smashed into the gun nest.

Idaeus chopped with his power sword and blood sprayed.

Uriel yelled, 'Grenade!' as he saw what was clutched in the severed hand. He kicked the hand into the gun nest's grenade pit and rolled a dead Space Marine on top. The frag blew with a muffled thump, the corpse's ceramite back-plate absorbing the full force of the blast.

'Thank you, brother,' muttered Uriel in relief.

Another Night Lord kicked his way into the gun nest, a screaming axe gripped in one massive fist. His blue armour seemed to ripple with inner fires and the brass edging was dazzling in its brightness. The winged skull icon hissed blasphemous oaths and Uriel could feel the axe's obscene hunger for blood.

Idaeus slashed his sword across his chest, but the blade slid clear. The warrior lunged, slashing his axe across Idaeus's shoulder and blood sprayed through the rent in his armour. Idaeus slammed his elbow into his foe's belly and spun inside his guard, hammering his sword through the Night Lord's neck.

He kicked him back outside as more enemies pushed themselves in. Uriel fired his pistol and rolled beneath a crackling power fist. He drove his combat knife into the gap between his enemy's breastplate and helmet, wrenching the blade upwards. Blood fountained and he yelled in sudden pain as the warrior fired his bolter at point blank range. The shell penetrated Uriel's armour and blasted a fist-sized chunk of his hip clear. He stabbed his opponent's neck again and again, stopping only when his struggles ceased completely.