Joe and his wife Asina were coming home to Hell.
Calmena was a primitive planet where descendants of abductees were enslaved by enemies of humanity, hoping to breed docile servants. It hadn't gone well for anyone.
A century ago, the Empire found the planet and began using it to trace the fractal demons back to their home. Joe and Asina's role has been helping the human slaves throw off the demonic yoke, always careful to camouflage their help as native ingenuity. In that century, Calmena has gone from isolated villages at the demons' mercy to independent towns and cities.
But the real power of the fractal demons was never on Calmena. When the fractal demons prepare to strike at the Empire, the Imperial missionaries must blunt or divert the blow, lest it completely crush the nascent Calmenan freedom.