Sub Officer Kyle Hawkins is two days out of his training as a Knight Hospitaller when he is sent to the jungle planet of Paradiso. After four years of gruelling training as a warrior of the NeoVatican, criticised by his superiors for his liberal, pacifistic theological views, he volunteers for the Paradiso assignment in an attempt to prove his worth. However, after arriving he finds that it is little more than a simple security detail, attached to a platoon of Fusiliers of the PanOceanian Light Infantry, guarding a sleepy MagnaObra research facility not far from the border of Yujingyu territory known as Alpha Four Four. The platoon Hawkins works alongside is led by Lieutenant Priya Shankar, a driven, serious minded officer whose professionalism makes her popular with her seniors, but seemingly cold and unapproachable to the soldiers under her command. Experienced with peacekeeping, disaster relief operations and ceremonial guard duties, Shankar has done everything expected of a Fusilier officer - except actual combat.

Shankar is assisted by her veteran deputy, Sergeant Jim Cochrane, a brash, gregarious ex-Indigo SpecOps soldier whose charisma and respected combat experience holds the loyalty of the platoon. When the sleepy research facility is probed by an unseen enemy force, Hawkins is propelled into action alongside the Fusiliers as political tension between PanOceania and Yu Jing quickly mounts. The secrets of what is hidden beneath the research facility are rumoured to hold information vital to the delicate relations between the Human Sphere, the mysterious alien Tohaa and the deadly forces of the EI. Major Lisette Beckmann, a beautiful but explosively violent operative of the PanO Strategic Security Division is sent to Alpha Four Four just as the fighting begins in earnest to act as a 'defence consultant'. Four very different soldiers with four completely different views on the conduct of war are left to lead the defence of Alpha Four Four as a full scale offensive is mounted against them, all the while being left in the dark as to what lies beneath MagnaObra's mysterious facility.