All Monsters Attack (怪獣総進撃 Kaiju Sou-Shingeki) is the first episode of Return of Ultraman.
The era of peace after Ultraseven's departure has ended. Strange Phenomenas have started happening all over the world. Severe weather and earthquakes have caused the awakening of monsters, thus starting the second age of monsters. In Japan, two giant monsters Zazahn, and Takkong rise from the ocean and start fighting in Tokyo bay, causing destruction in the process. MAT (Monster Attack Team) is called into action to quell the kaiju assault. During the attack, a boy named Jiro Sakata ran to the car company to tell his older siblings that monsters were attacking, and ran off to them, with a race car driver Hideki Go ran off to chase after him. Jiro went through the police to get them, and Go got him to safety. Zazahn is defeated and dies leaving Takkong remaining. MAT landed to ground when a mother told the team that her son Hiroshi went to the top of the building to release the birds out of their cages. Oka was about to go in, but Go went to the building to help Hiroshi release the birds, and got back down stairs until they noticed a dog chained in, so Go went back in, and released the dog. Takkong crushed the building and collapsed on Go covering the dog, and Hiroshi. Then a light flashed with Takkong retreating back into the ocean. Hiroshi went to get help until Go fainted.
The doctors took him to the hospital for treatment. Aki Sakata, Jiro's older sister, MAT, and Hiroshi, and his mother helping the hospital. They but a mask on him connected to a chamber of water to know he's breathing, and gave him a needle. Ken Sakata, the oldest in the family arrived to tell Go that the race car the Shooting Star was finished. The bubbles in the chamber stopped which mean't he died. The Sakata siblings went in the room with the Shooting Star. They put flowers, a photo, and a race car toy in, and Ken poured oil on the car, and burned it to say farewell.
Back at the hospital a light appeared revealing the new hero Ultraman who was impressed of Go's courageous act that he saved a dog, and a boy if it cost his life. He merged inside Go's body, and he was revived seeing that he was in the hospital,even surprising a nurse. MAT got a call from the hospital to hear that Go was back to life. Go returned to the Car Company seeing that the Shooting Star was burned for his tribute of his heaven. Go went to Ken's office to tell him that they should make the Shooting Star 2, but Ken refused and for his heroism, Captain Kato offers him a job as a member of the MAT force. Go suddenly heard a voice far away and went to the car, and left without a word initially unaware of the powers he possesses.
Kato got a contact from Oka that a third monster appeared in Asagiri Volcano attacking a village. MAT engage the monster and took the people to safety. Meanwhile a girl noticed her grandfather trapped under, and couldn't get him out, until Go arrived to save him, and lifted the metal off of him. Suddenly a light was seen and Go transformed into Ultraman to battle the fire-breathing beast. He finished him off with his Specium Ray, and was defeated. Morning came, and MAT members were having a picnic, and the boys were ordered by Oka to wash their hands in the river. They noticed Go laying, and he woke up, and was presented by Kato as a new member of the team, with team introduced themselves, and went to have their picnic with Go invited, until Go heard the voice of the hero who introduced his name as Ultraman and told Go to keep it a secret.
- Hideki Go (郷 秀樹 Gō Hideki): Jiro Dan (団 次郎 Dan Jirō)
- Takeshi Minami (南猛 Minami Takeshi): Shunsuke Ikeda (池田 駿介 Ikeda Shunsuke)
- Ippei Ueno (上野一平 Uneo Ippei): Mitsui Hatashi
- Yuriko Oka (丘ユリ子 Oka Yuriko): Mika Katsuragi (桂木美加 Katauragi Mika)
- Katsushiro Kato (加藤勝一郎 ): Nobuo Tsukamoto (塚本信夫 Tsukamoto Nobuo)
- Fumio Kishida (岸田文夫 Kishida Fumo): Nishida Ken (西田健 Ken Nishida)
- Jiro Sakata (坂田 次郎 Sakata Jirō): Kawaguchi Hideki (川口英樹 Hideki Kawaguchi)
- Aki Sakata (坂田アキ Sakata Aki): Rumi Sakakibara (榊原るみ Sakakibara Rumi)
- Ken Sakata (坂田健 Sakata Ken): Shin Kishida (岸田 森 Kishida Shin)
- Hiroshi (ひろし Hiroshi): Sanpei Godai (伍代参平 Godai Sanpei)
- Ultraman Jack (ウルトラマンジャック Urutoraman Jakku): Eiichi Kikuchi (菊池英一 Kikuchi Eiichi)
- Takkong (タッコング Takkongu): Takanobu Toya (遠矢孝信 Tōya Takanobu)
- Zazahn (ザザーン Zazān): Eiichi Kikuchi (菊池英一 Kikuchi Eiichi)
- Arstron (アーストロン Āsutoron): Takanobu Toya (遠矢孝信 Tōya Takanobu)
Return of Ultraman Vol 1 Episodes 1-4.
- The name of the episode is shared with the Japanese name of the Toho film Destroy All Monsters, and the English name for the episode is shared with another Toho film, All Monsters Attack.
- Due to Ultraman Jack's NG suit, the episode was reshot, so this is the only appearance of the suit.
- This episode was later featured in Ultraman Retsuden episode 30 "All Monsters Attack! Birth of Jack!!". 
- The Ultraman Orb episode, "Juggler Dies!" is a tribute to this episode.