Iax had a pronounced axial tilt, and the southern hemisphere’s autumn was coming to an end. It was evening and growing cold as the cleansing team climbed down from their transports. They unspooled their lines and passed through a spray gate, the only gap in the complex of bubble tents around the field. Drenched in strong antibiologics, they paced to and fro, the huge hoses leading from the tankers looped over their backs and pointed at the ground. Their human forms were lost in the bulk of their protective suits, so that servitor and true man were hard to tell apart. Blasts of boiling water were followed by sheeting sprays of anti-virals. Bio-killers swept across the rockcrete. The water sent up huge columns of condensing vapour into the chill air. Appearances were maintained.

When the cleansing had been done, priests in biohazard surplices marched out from the interconnected domed tents crowding the apron. They trailed back and forth over the antiseptic ground, flicking aspergillums full of sanctified oils to kill those psychic corruptions that chemicals could not purge.

Finally, the quarantine masters – the mid-ranking medicae officials, the Frater Hospitaller Majoris Inferior of the local Adeptus Ministorum and purity officers from the commissariat – came out from the tents, inspected the work, gave their approval and affixed their seals to the relevant order parchments. Only then was a lighter given clearance to land.

The whole process took half an hour, every single time.

The ground crew were kept on hand in case the cleansing had not been performed satisfactorily. With relief, they watched their superiors march back into the clutter of bubble tents around the field. As the last closure zipped shut, the ground crew wearily rolled up their disinfectant hoses, retreated back through the spray gate to their service vehicles and sped beetle-fast across the landing fields to grab forty minutes of rest, one cleansing closer to the end of their eighteen-hour shift.

The field was now yielded to several medicae equipped with bulky auspexes attached to their suits with sealed, flexible pipes. Angry red lights flickered condemnatory patterns on the instruments’ upper surfaces.

Bright points shimmered against the evening thousands of feet into the sky. The lighter came in fast. When it had grown to a growling, angular shape, black against the low sun, the medicae set off cleansing bombs around the landing apron that shot out plumes of astringent white smoke in noisy whooshes. The lighter touched down in a mist of anti-biological agents, dropped its ramps without powering down its engines, and was away as soon as the last injured soldier was out of its hold.

In this way, Tullius Varens of the Prandium 30th Ultramar Auxiliary Regiment came to Iax. He shuffled onto the apron with a hundred others like him, blinking against daylight after a week inside a dimly lit voidship cell. He carried nothing but his lasrifle, his flak armour and the uniform on his back. Everything else he owned had been incinerated.