While walking around in the streets, Jiro spots Hideki Go, although his caretaker doesn't believe him. Shortly after Jiro saw Go, Zaigon emerges and attacks, trampling buildings.
TAC is quick to respond, sending jets in. Upon arrival, TAC spots Jiro and his caretaker trapped on the ground with all the fires brewing around. Seiji Hokuto goes on land to rescue the 2 from Zaigon as he advances toward them. As Hokuto is about to shoot Zaigon with a bazooka, Hideki Go appears in front of him. Hokuto tells him to move out of the way but he refuses so Hokuto shoves him aside. Go suddenly fired a Laser Cannon he had at Zaigon, which he calls the "Ultra Laser", causing Zaigon to vanish.
Jiro Sakata was excited to see his brother figure return, before being gently pulled away as Go was injured during the attack and sent to TAC hospital for recovery. The team recalls that Go was a member of the previous attack force MAT and that he died during the battle with Alien Bat and Zetton II.
TAC would then settle into an intense debate of whether to accept Go as a new member, and Seiji is scolded for arguing about how Go's actions prevented him from firing at Zaigon. Afterwards, when Seiji and Yuko visited Go in his room with Jiro and his female companion, Seiji begin to suspect Go when Jiro saw Go handle the chopsticks he had been given to eat the food Jiro gave him in his left hand, when Go is right handed.
Just then Zaigon reappeared and Go lept out of his bed, locking the door and trapping Jiro along with his caretaker inside. Hokuto tried to open the door, but Go shot at him, and that was when he revealed his true identity as Alien Antira. Hokuto quickly freed Jiro, who went after the alien, thinking it was Go Hideki. As Jiro reached the rooftop, he saw the alien in disguise ordering Zaigon to destroy the building as soon as possible. Jiro was angry, and charged at the villian disguised as his idol, but he was taken hostage. Hokuto freed Jiro. Antira leaped around dodging Minami's and Hokuto's gunfire, but when he landed on the roof he was shot by Hokuto's rocket launcher, killing him.
As the building was filling up with smoke, making it hard for Jiro to breath, Minami and Hokuto transformed into Ultraman Ace, putting Jiro on the ground safely before turning to face his opponent, Zaigon. Ace battled with the rhino-like choju himself. Ace then proceeded to taunt Zaigon by using a red flag as a cape, bullfighting with the choju, but the taunting didn't last long after Zaigon used his flames. After shooting the choju in the mouth with the Light Ball, Ultraman Ace decapitated Zaigon with the Ultra Knife. Ultraman Ace then took Zaigon's head and erected it as a tomb for the monster.
Afterwards, Jiro and his caretaker along with Minami and Hokuto swung on the swings. When suddenly Jiro got up from the swing and looked to the skies, seeing a vision of Hideki Go. As he saw the vision, Jiro recited the 5 Ultra Pledges.
- Seiji Hokuto (北斗星司 Hokuto Seiji Hokuto Seiji): Keiji Takamine (高峰 圭二 Takami)
- Yuko Minami (南夕子 Minami Yūko): Mitsuko Hoshi (星光子 Hoshi Mitsuko)
- Dan Umezu (梅酢ダン Umezu Dan): Umezu Akinori (梅酢秋則 Akinori Umezu)
- Goro Ryu (竜五 郎 Ryu Goro): Tetsurō Sagawa (瑳川哲朗 Sagawa Tetsurō)
- Ichiro Yamanaka (山中一郎 Yamanaka Ichiro): Okita Shunichi (沖田駿一 Shunichi Okita)
- Tsutomu Konno (今野勉 Konno Tsutomu): Masaaki Yamamoto (山本正明 Yamamoto Masaaki)
- Noriko Mikawa (美川 のり子 Mikawa Noriko) Keiko Nishi (西恵子 Nishi Keiko)
- Kozo Yoshimura (吉村公三 Yoshimura Kozo): Koyo Sano (佐野光洋 Sano Koyo)
- Kaji Yoichi (梶洋一 Yoichi Kaji): Katsumi Nakaiyama (中山 勝己 Nakaiyama Katsumi)
- Yapool (ヤープル Yapurū Voice): Hirofumi Takada (高田裕史 Takada Hirofumi)
- Alien Actira (アンチラ星人 Anchira Seijin Voice): Hiroshi Takada (高田裕史 Takada Hiroshi)
- Narrator (ナレーター Nareta): Shin Kishida (岸田森 Kishida Shin)
- Jiro Sakata (坂田 次郎 Sakata Jirō):Kawaguchi Hideki (川口英樹 Hideki Kawaguchi)
- Rumiko Maruno (村野 ルミ子 Maruno Rumiko):Iwasaki Kazuko (和子岩崎 Kazuko Iwasaki)
- Fake-Hideki Go (にせ郷秀樹 Nise Gō Hideki): Jiro Dan (団 時朗 Dan Jirō)
- Ultraman Ace (ウルトラマンエース Urutoraman Ēsu): Shoji Takeuchi (武内正治 Takeuchi Shoji)
- Zaigon (ザイゴン Zaigon): Toru Kawai (河合 徹 Kawai Tōru)
- Ultraman Ace Volume 3 features episodes 9-12.