被吉恩軍破壞的側面4，摩爾。 在殘骸漂浮的《桑德博爾特宙域》中，因失去故鄉而倖存下來的摩爾兄弟團，為了排除盤踞在宙域的吉恩軍的客廳·死亡師，展開了作戰。 摩爾兄弟團的飛行員 以奧·富林明古 在戰鬥中被吉恩軍的王牌狙擊手 達里爾·洛倫茲 擊落，但還是逃脫了。 殺死敵方飛行員，搶走機動戰士，嘲笑達里爾的脚進行挑釁。 對於殺死戰友，侮辱自己和夥伴們的以奧，達里爾决心復仇。

達里爾等人協助卡拉教授的重用P設備研究。 另一方面，對於以奧的全武裝高達的威脅，被命令死守雷霆宙域的客廳·活死人軍團的巴羅斯艦長，决定投入能够對抗敵人高達的實驗機，决定作為其最後零件的飛行員。 被選為飛行員的達里爾被迫切斷剩下的右手。 一度拒絕施術的卡拉，為了在本國的父親的救命，接受了塞克斯頓的說服。 師團的命運將交給搭載了重用P設備的塞科·紮克和失去手臂的達里爾。

補給物資和學生兵到達消耗了飛行員和機動戰士的航空母艦比哈伊夫。 為把他們送到死地的任務而苦惱的古蘿迪亞依賴藥物來逃避現實。 對那樣意志消沉以奧覺得很生氣。 哥尼力斯卻照顧她。 另一方面，被卡拉說出與重用P設備有關的理由的達里爾鼓勵“活下去”。 然後，聯邦軍奪回雷霆宙域的總攻擊開始了。慕亞兄弟和活死人軍團的殲滅戰愈演愈烈。 在塞科·紮克壓倒敵艦隊的達里爾，終於與以奧的全武裝高達完成了第三次的會敵。

With both sides suffering massive casualties, the Full Armor Gundam engages in a final showdown with the Psycho Zaku. Meanwhile, the surviving members of the Moore Brotherhood board the Dried Fish to take it over, but the remaining members of the Living Dead Division refuse to be taken prisoner and plan to self-destruct the vessel along with everyone on board. The Federation survivors manage to neutralize the Zeon crew and seize the Dried Fish, while Io and Daryl's battle results in heavy damage to both of their mobile suits. A Zeon reinforcement fleet then arrives and captures Io and the Federation survivors while rescuing any remaining Living Dead members.

During the Earth Federation's assault on the Zeon's A Baoa Qu fortress, Io and his comrades escape captivity while several Zeon forces retreat, taking Io's Gundam with them. Eight months after the end of the One Year War, the Federation continues to battle Zeon remnants on Earth. The Federation carrier Spartan enters Earth orbit, but a Musai-class ship launches its Komusai shuttle for a kamikaze run on it. Suddenly, a new Gundam piloted by Io is launched from below and it slices the Komusai in half to save the Spartan.

Due to the emotional trauma Karla suffered during the One Year War, her mind has regressed back to that of an adolescent child with the Zeon Remnants now trying to take care of her in hopes of her adult mind to recover. Daryl's Acguy squadron heads to a South Seas Alliance-controlled city in Southeast Asia to retrieve a spy, but their cover is blown and they must fend off against the island's mobile Suits. Meanwhile, the Spartan is confronted by a South Seas Alliance mobile suit Squadron, with Io's former commander and lover Claudia leading them.

As tensions are high between the Spartan and the South Seas Alliance, Daryl's team is also having trouble in their hands finding their way out against a counterattack by the cult group. During the battle, several cultists break into the Spartan while Daryl manages to extract the Zeon spy out of the island. Meanwhile, Io and Bianca storm through the squadron of Dodai YS units to take back Claudia, but they are thwarted by Gouf pilot Chow Ming. Despite the temporary victory, Io learns the truth about who is running the South Seas Alliance.