As the mighty Dark Angels descended upon Macragge, no one noticed a small civilian ship crossing the vast distance to arrive at the Helion Orbital Platform on the same day.
It was a starship from Calth, from that painful scar upon the Five Hundred Worlds that had yet to heal.
The once-rising world had been consumed by the flames of the Battle of Calth. Later, Guilliman dispatched the Adeptus Mechanicus to try to save Calth. Weather-control devices formed a permanent, dense barrier in the planet's atmosphere to block the deadly harm of stellar radiation.
Though the radiation, weakened by the atmosphere, could no longer kill an ordinary person wearing basic protective gear, countless people of Calth had still lost all attachment to their homeland. They chose to board starships and head for new worlds.
The Ultramarines stationed in Calth's wastelands provided free one-way tickets to every ordinary person who wished to leave. Civilian ships organized by the Ultramarines carried tens of thousands of Calthians away from their homes.
Naturally, free tickets did not come with much comfort. These destitute Calthians crowded onto the ships with fear and trauma in their hearts. The vessels were packed to bursting, and air recycled countless times carried an unpleasant stench that filtration could not remove as it entered their long-numbed lungs.
Fortunately, the long journey had finally come to an end. The immigrant ship arrived at a gravity docking platform orbiting Macragge. They would disembark here and be assigned suitable destinations by the immigration center.
Though this was also part of Macragge's Orbital Platform, the defense system revision proposal jointly issued earlier by Auguston and Pollux meant that no starship, including civilian vessels, could approach Macragge any longer.
And because of the unexpected arrival of the Dark Angels, the immigration center was exceptionally crowded.