The catacombs stank. Thousands of years ago, they had been used to channel the waste effluent of the Invernus’ manufactoria out into the rad-wastes beyond the hive city, though they had long since been abandoned and closed off. Even after those millennia, however, the chemical reek of the place and the stench of decay persisted, even through the filters of Watch-Sergeant Cervantes’ helmet. No one had been down here since that time, not even scavvers of the underhive or the reclamation servitors of the manufactoria.

Which meant, of course, that it was the perfect place for xenos to infiltrate the city.