'Incoming!' he yelled and dived over a pile of debris into a crater as the thunder of two battle cannons echoed across the gorge. He felt the awesome force of the impacts behind him, even through the ceramite of his power armour. His auto-senses shut down momentarily to preserve his sight and hearing as the massive shell exploded, the pressure of the blast almost crushing him flat. Red runes winked into life on his visor as his armour was torn open in half a dozen places. He felt searing pain and cursed as he yanked a plate-sized piece of sizzling shrapnel from his leg. Almost instantly, he could feel the Larraman cells cloting his blood and forming a protective layer of scar tissue over the wound. He had suffered much worse and shut out the pain.

The two surviving Leman Russ tanks rumbled downhill, smashing the smoking remains of the Salamanders aside with giant dozer blades. Furious gunfire spat from their hull-mounted heavy bolters, sweeping across the bunker's face and the bridge, throwing up spouts of water and rock. None hit the Ultramarines and Idaeus shouted, 'Up! Come on, keep moving!'

The Space Marines rose and continued running towards the comparative safety of the far side of the bridge. More tanks and infantry spilled over the ridge, following in the wake of the Leman Russ battle tanks. Las-blasts fired at the Space Marines, but the range was too great.

Then, at the edge of his hearing, Idaeus heard the welcome boom of a Thunderhawk gunship's engines and saw the angular form of the aerial transport sweep from above the jungle canopy. Rockets streaked from its wing pylons, rippling off in salvoes of three and the ridge vanished in a wall of flames. Heavy cannons mounted on the hull and wings fired thousands of shells into the rebels, obliterating tanks and men in a heartbeat.

Idaeus punched the air in triumph as the Thunderhawk swept over the ridge and circled around for another strafing run. He jogged leisurely into the sandbagged gun nest, the Space Marines who had followed him taking up firing positions.

'Uriel,' voxed Idaeus. 'Are you ready to get out of here?'

'More than ready,' replied Uriel from the bunker behind Idaeus. 'But we have a problem. Tomasin was killed in the shelling and he had the detonators. We can't blow the bridge.'

Idaeus slammed his fist into a sandbag. 'Damn it!' he swore, teeth bared. He paced the interior of the gun nest like a caged grox before saying, 'Then we're going to have to hold here for as long as possible and pray the Guard can realign their flank in time.'

'Agreed. The Emperor guide your aim, captain.'

'And yours. May He watch over you.'

Uriel shut off the vox-com and slid a fresh magazine into his bolt pistol, staring out at the flame wreathed hillside. The distant Thunderhawk had circled around, guns blazing at something Uriel could not see. Fresh explosions blossomed from behind the ridge as more traitors died.

Suddenly shells burst around the gunship and streams of fire, bright against the dark sky, licked up from the ground. Uriel swore as he realised the traitors were equipped with anti-aircraft weapons. The gunship jinked to avoid the incoming fire, but another stream of shells spat skyward and seconds later the gunners had the Thunderhawk bracketed. Thousands of shells ripped through the gunship's armour, tearing the port wing off. The engine exploded in a brilliant fireball. The pilot struggled to hold the aircraft aloft, banking to avoid the flak, but the gunship continued to lose altitude, spewing black smoke from its stricken frame.

Uriel watched with horror as the Thunderhawk spiralled lower and lower, its wobbling form growing larger by the second.

'By the Emperor, no!' whispered Uriel as the gunship smashed into the ground just before the bridge, skidding forwards and trailing a brilliant halo of sparks and flames. The wreckage crashed into the unoccupied bunker, demolishing it instantly, and slewing across the bridge towards the Ultramarines with the sound of shrieking metal. The remaining wing sheared off, spinning the flaming gunship upside down and tearing up the roadway. The gunship ground onwards, finally coming to a halt less than two hundred metres from the gun nests.

Uriel let out the breath he had been holding. Movement caught his eye and he saw more enemy vehicles rumbling through the swirling black smoke towards the bridge.

'Targets sighted!' he shouted. 'Enemy tanks inbound. Mark your targets and fire when you have a clear shot!'

The lead rebel armoured column consisted of dozens of Chimeras, daubed in blasphemous runes. Uriel snarled as he recognised the winged skull motif of the Night Lords crudely copied onto the Chimeras' hulls. There could be no doubt now. The taint of Chaos had come to Thracia. Each vehicle mounted a powerful searchlight, sweeping blindingly back and forth in random patterns across the bridge as they charged. Missiles and lascannon blasts pierced the darkness, and the night was illuminated by scores of exploding tanks. No matter how many the Ultramarines killed, there were more to take their place. Soon the bridge was choked with burning wrecks. Hundreds of screaming soldiers dismounted from their transports, working their way forward through the tanks' graveyard.

Uriel fired shot after shot from his pistol. It was impossible to miss, there were so many. The darkness of the gorge echoed to the sounds of screams and gunfire. But Uriel was not fooled by the slaughter they were wreaking amongst the ranks of the traitors. Their ammunition was finite and soon the battle would degenerate into bloody close quarter fighting and, though they would kill many hundreds, they would eventually fall. It was simply a question of numbers.

He reloaded again and wished there was something else he could do, cursing Sevano Tomasin for dying and condemning them to this ignoble end. He pictured again the image of the Techmarine incinerated by the chain-reacting melta charge in his equipment pack.

Something clicked in Uriel's head and he stopped.

No, it was insane, utterly insane and suicidal. But it could work. He tried to remember a precedent in the Codex Astartes, but came up with nothing. Could it be done? A frag wouldn't do it and only the assault troops had been issued with kraks. He checked his grenade dispenser. He had one breaching charge left.

His mind made up, he grabbed a Space Marine from the firing step, shouting to be heard over the bolter fire. 'I'm heading for the captain's position. Give me covering fire!'

The man nodded and passed on his order. Uriel ducked out the ragged doorway and crouched at the corner of the bunker. Streams of las-blasts and bolter rounds criss-crossed the darkness causing a weirdly stroboscopic effect.

Volleys of sustained bolter fire blasted from the bunker and Uriel leapt from cover, sprinting towards Idaeus's position. Instantly, lasgun fire erupted from amongst the burning tanks. Each shooter was silenced by a devastatingly accurate bolter shot.

Uriel dived behind the gun nest and crawled inside on his belly.

Idaeus, bleeding from a score of gouges in his armour, directed disciplined bolter fire into the traitors' ranks. Two Space Marines lay dead, the backs of their helmets blasted clear, and Uriel was suddenly very aware of how much less protection there was in the gun nest than the bunker.

Idaeus spared Uriel a glance, shouting, 'What are you doing here, Uriel?'

'I have an idea how we can blow the bridge!'

'How?'

'The assault troops have krak grenades. If we can attach some to one of the melta charges on the bridge supports it could set of a chain reaction with the others!'

Idaeus considered the idea for a second then shrugged. 'It's not much of a plan, but what choice do we have?'

'None,' said Uriel bluntly. Idaeus nodded and hunkered down in the sandbags, snatching out his battered vox. Hurriedly, he explained Uriel's plan to the sergeant of the assault troopers, receiving confirmation as to its feasibility of execution.