In the Universal Century year 0079, the space colony known as Side 3 proclaims independence as the Principality of Zeon and declares war on the Earth Federation. One year later, they are locked in a fierce battle for the Thunderbolt Sector, an area of space scarred by the wreckage of destroyed colonies.

The mission to recover Zeon's Reuse P. Device technology leads Daryl Lorenz and his unit to the Rig, a network of oil platforms inside Nanyang Alliance territory now repurposed as a floating city. The Rig is a haven for refugees and deserters from both sides of the war, all living under the watchful eye of the warrior monks of the Alliance. Ordered to infiltrate the Rig undercover, Lorenz and his team must make contact with a Zeon operative and begin a covert operation to learn the secrets of the Nanyang Alliance and its leader, Sojo Levan Fu, who plans to do far more than simply mass-produce the Psycho Zaku...