Set in a fictional universe (Universal Century year 0079 according to the Gundam Calendar), the Principality of Zeon has declared independence from the Earth Federation and subsequently launched a war of independence called the One Year War. The conflict has directly affected every continent on Earth, nearly every space colony, and lunar settlement. Zeon, though smaller, has the tactical upper hand through their use of a new type of humanoid weapon called mobile suits. After half of all humanity perishes in the conflict and much of Earth's ecosystem, the war settled into a bitter stalemate lasting over eight months.
The story begins with a newly deployed Federation warship, the White Base, arriving at the secret research base located at the Side 7 colony to pick up the Federation's newest weapon. However, they are closely followed by Zeon forces. A Zeon reconnaissance team member disobeys mission orders and attacks the colony, killing most of the Federation crew and civilians in the process. Out of desperation, young Amuro Ray accidentally finds the Federation's new prototype arsenal—the RX-78 Gundam—and manages to beat back Zeon forces. Scrambling everything they can, the White Base sets out with her newly formed crew of civilian recruits and refugees in her journey to survive.
On their journey, the White Base members often encounter the Zeon Lieutenant Commander Char Aznable. Although Char antagonizes Amuro in battle, he takes advantage of their position as Federation members to have them kill members from Zeon's Zabi family as part of his revenge scheme since he is the son of the original founder of Zeon and the nation's namesake. Amuro also meets Ensign Lalah Sune, with whom he falls in love but accidentally kills when facing Char. When the Federation Forces invade the Fortress of A Baoa Qu to defeat the Zeon forces, Amuro engages in a final one-on-one duel against Char due to each blaming the other for Lalah's death. Having realized he forgot his true enemy, Char stops fighting to kill the last surviving Zabi member, Kycilia Zabi. Amuro then reunites with his comrades as the war reaches its end, leaving behind the Gundam as it was rendered inoperable after his battle. The conflict officially ends when the prime minister of Zeon surrenders to the Federation, losing the majority of its industrial capabilities and reverting itself to a republic. However, many remnants of Zeon's military go into hiding, licking their wounds in the hopes of retaliating against the Earth Federation at a time of their choosing.
