Das Schiff der Celestial Being ist zerstört, und die Gundams kampfunfähig. Setsuna versucht Alejandros Truppen zu stoppen, doch steht im später ein viel größerer Feind gegenüber.
Setsuna continues to struggle against Alejandro's weapons and shield. Exia docks with the GN Arms and evens the odds with the Alvatore. Setsuna succeeds in destroying Alejandro's shield but the GN Arms is destroyed in the process. Meanwhile, Sergei and Soma search for Kyrios. Allelujah wishes to know the meaning of their fight and unites with Hallelujah to face the two GN-Xs. Allelujah destroys Soma's GN-X and cripples Sergei but does not finish them off when he recognizes Soma as someone from his past. With his mobile armor damaged, Alejandro emerges in a golden mobile suit. Setsuna uses Exia's 'trump card' (his physical GN Blade) to bypass Alejandro's GN Shield and defeat him. Alejandro gets a message from Livonze revealing that Alejandro was a pawn and that Livonze is the true mastermind, right before Alvatore explodes. Graham then appears in his GN Drive-equipped Flag and engages Setsuna. Setsuna and Graham finally reveal themselves to each other and destroy each other's mobile suits. On Earth, Marina reads a letter from Setsuna questioning the current state of the world and how he hoped she'd help him learn the answers. Setsuna lies unconscious as Exia floats in space.
Four years later (A.D. 2312), Saji writes a letter to Louise from space and says he is still waiting for her. He sees a GN particle trail in the distance and recognizes it as a Gundam. The UN has become the Earth Sphere Federation and all countries have disarmed and formed the ESF peacekeeping force. On Celestial Being's asteroid base, Ian talks with Wang Liu Mei about deploying their new mobile suits. Liu Mei asks to see the O Gundam, the first generation unit, and then comments that the OO Gundam will change the world.
Un MS des Nations Unies parvient à abattre une partie de l'équipage du Ptolémée, notamment Chris et Lichty. Setsuna et Lassé, de leur côté, démarrent leur affrontement contre l'Alvatore, le Mobile Armor venu soutenir l'ONU et piloté par le traître de Celestial Being, Alejandro Corner. Cette bataille décisive apportera-t-elle les réponses que cherchait Setsuna ?
漆黒の宇宙に次々と散る命。刹那は自分の信念を誇示するように、相対する歪んだ存在を否定するように、最後の戦いに身を投じる。衝撃と感動のファーストシーズン最終回!!
生命持续在漆黑的太空中消逝。舰艇受创沈没、MS爆炸四散。刹那为了展示自身的信念、否定已被扭曲的时势，而毅然决然地投入最後之战。
