On 0805.010M42, following a series of strike missions by the Tau Air Caste, remote sensors and orbital imagery pinpointed a powerful energy source at one of the target sites within the barrier mountains. Tau planners immediately dispatch a mobile task force under Shas'el R'mirr to investigate the source, situated close to the Imperial held Grenton mines.
On reaching the ruined settlement the task force advanced with caution, having identified the energy source as a damaged plasma reactor, an ancient artefact dating back to the dark age of technology. Sensors and advanced reconnaissance teams showed the site to be undefended but the Tau's caution proved well founded. As they drew close to the reactor the air shimmered as the bulky forms of the Imperium's feared Space Marines materialised around the reactor site.
Operating from a strike cruiser orbiting Tarsis Major, Marines of the Blood Angels chapter were able to beam directly into the combat zone with pinpoint accuracy thanks to a lock on the reactor's energy signature. Even so, their boldness cost them as one squad was lost in a teleporter mishap. Soon vicious close quarter fire fights erupted throughout the settlement with the Blood Angel's sustaining heavy casualties before closing with the Tau to engage them in hand to hand combat. They might have won the day against less experienced opponents, but this cadre were hardened veterans of the long running Tarsis campaign and they maintained strong fire discipline even as their comrades were butchered. Their numbers diminished, the Blood Angels had no choice but to fall back and try to slow the Tau from reaching the reactor with hit and run attacks. Shas'el R'mirr gave the order to scour the ruined settlement and the Tau under his command methodically cleared each cluster of buildings, flushing out their prey with barrages of smart missiles and gunning down the survivors as they were forced into the open.
As dusk turned into night the Tau finally secured the reactor, which was supplying power to the nearby mining operations at Grenton. When orbital surveillance identified a column of armoured vehicles exiting Grenton the Tau destroyed the reactor rather than risk it falling back into Imperial hands.
Even as Shadowstrike prepared for a new Tarsis offensive he realised that the Imperium's overwhelming dominance of space would have to be challenged. Fortunately, even as the fighting intensified on Tarsis new cadres and ships had arrived in the region to aid his efforts.
Now came the test. Many times before the Imperium had captured territory using armoured columns, but had then surrendered that territory to perfectly timed counter attacks launched by Shadowstrike’s forces. This time it would be different.
As in previous offensives the Imperial assault ran out of steam and Shadowstrike launched his highly mobile counter offensive, attacking the Imperial forces from three directions with carefully timed manoeuvres. The fighting was intense, but Jeffries’ had planned for the assault, being a veteran of the Tau wars and Shadowstrike in particular. This time his troops were arranged in mutually supporting dispositions, preventing the Tau from picking off his units when they were overextended. In stead of holding onto as much ground as possible, Jeffries retreated a little to strongpoints and then allowed the Tau to attack.
The fighting came to a head on the flanks of Jeffries’ salient, where strong Tau armoured formations, led by Hammerhead tanks, were prevented from breaking through by brave assaults from veteran units. With this armoured assault blunted and Tau crisis suits bottled up in a stalemate in front of the Librian main positions, the right flank became crucial. Kroot mercenaries and fire-warriors formed the main assault here, but Hellhound flame tanks decimated the kroot lines, blunting that attack as well.
By the second day the Librians were beginning to become desperate. The battle seemed to rage with ever greater intensity and neither side seemed willing to give up. The Librians were losing men at a horrific rate and it seemed as if the Tau would once again force an Imperial retreat, but just as the Librians were down to their last rounds the morale of the Tau cracked and the commander on the ground ordered a retreat from the Imperial positions.
The fighting subsided and with a great cheer the PDF reinforcements arrived to consolidate the Imperial victory. Casualties were heavy on both sides but this time the Librians had recorded a substantial, if not overwhelming victory over commander Shadowstrike. With the Imperial dominance in space and the chances of a swift victory on the ground dashed, Shadowstrike now knew that he would need reinforcements to finish off the Imperium on Tarsis.