While the mechanized forces of Ingelmia begin to encroach on the Kingdom of Arandas, the 8th Independent Unit of Arandas is ordered back to their headquarters. Along the way, a civilian convoy is attacked by Ingelmian forces. Tokimune Susumu, a rookie pilot, disobeys orders and tries to rescue the civilians only to get his own Trail Krieger mech destroyed in the process. However, an engineer named Jamie Hazaford jumps out from the passenger's side of the truck and reveals the cargo she was carrying, a brand new robot called the Argevollen. With no other options, Jamie shoves Tokimune in the pilot's seat while his comrades battle with the surrounding enemy forces, and starts up the robot's operating system. Tokimune then manages to use the Argevollen to destroy the remaining enemies.