In the prologue (set during the Battle of A Baoa Qu in December U.C.0079), Zeon ace pilot Anavel Gato returns from combat to find Admiral Aiguille Delaz telling him of the deaths of Gihren Zabi and Kycilia Zabi, as the Zeon forces surrender. Despite the shock defeat, both men retreat and plan the return of Zeon. In October U.C.0083, the Federation space carrier Albion delivers two Gundam Development Project (GDP) prototypes, the RX-78 GP01 Zephyranthes and the GP02A Physalis, to the Torrington Base in Australia for ground testing under the aegis of Anaheim Electronics engineer Nina Purpleton. Because of lax security, a Zeon mole helps Gato infiltrate the base and hijack the GP02 just after its nuclear weapon is loaded in the middle of the night. Having witnessed Gato activate the mobile suit, Ensign Kou Uraki takes over the Zephyranthes and prepares to face him just as Zeon forces assault the base.