The story takes place during the One Year War, parallel to the story of the first Gundam. A young Federation officer named Silo Yamada, who is assigned to the Earth Front, meets the enemy, the female pilot Aina Sakhalin of the Zeon Army, in an accidental exchange of fire. The two young people, who have good intentions for each other, have to fight each other because they are on the opposite side, struggling to maintain their relationship during the war; on the other hand, Silo and the members of the 08th MS team he leads gradually develop friendship and trust in the constant battles.