The Planetary government refused to believe there was a Genestealer Cult threat on Ieaid. That foolishness has led to this, the only remaining toehold for the Imperium on the planet: the PDF fort manned by a few score troopers atop a small but high plateau, located in the wastelands near the Capital City.
This view from above the approaching Cultist army shows the forts' two walls, (top and bottom), barracks on right; Commander's quarters above and left of front gate; Vehicle storage to its left; Communication tower center; and power house upper left. The wall at top guards a small twisting road that follows its hairpin turns to bottom of the plateaus base...
Opposite view of the Fort...The Genestealer Cult Army begins its attack (the Kroot figs and 'zombies' stand in for the masses)...The PDF troopers on the wall take some casualties as well...One defender falls off the wall...The first Cultist vehicle is destroyed...The Cultists push on, but begin to take serious losses...The PDF suffer as well...The Cultists are close now...The bikes are eliminated...The first Ridgerunner is destroyed as well as many cultists...As the Rock Grinder prepares to assault the gate (with the governor ties to the fight), the gate opens and the defenders Sentinels lash out and destroy it!...Losses are mounting up for the PDF as well however...Heavy losses in fact are degrading the defenses...As the Cultists own Sentinels advance and a charge is made for the gate, the fight remains in the balance...The Cultists lose their last heavy weapon platform as the Ridgerunner explodes...A Sentinel and many Cultists fall to the PDF fire...The charge at the gate is very costly for the Cultists...Yet more Cultist are lost before the walls...But even as more Cultists arrive, the Commissar (left) and his few men stand their ground...More Cultists fall before the gate, as the defenders have massed their Sentinels for good effect...But the PDF has established Vox communication with the last remaining Imperial Cruiser in orbit. The Wall is abandoned (note troopers above and to left of gate) and the gate closed as a few Cultists reach the inside...With no heavy weapons available to breach the gate, the PDF forces begin to evacuate Ieaid by shuttle craft sent by the Imperial Navy...The handful of Cultists who reached the inside, are quickly eradicated. It takes nine turns for the Cultists to bring up some mining tools to destroy the gate. But by that time, the defenders have abandoned the fort, and the planet. The long struggle has come to an end as the Genestealers have been successful. What they don't know of course, is when the Tyranid Fleet arrives, they will all be devoured and absorbed into the Hive!