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UFO Robot Grendizer vs. Great Mazinger (1976) Plot Summary & Timeline

UFO Robot Grendizer vs. Great Mazinger (1976) movie poster

UFO Robot Grendizer vs. Great Mazinger is a 1976 animation and adventure film directed by Osamu Kasai. This page retells the whole story in 154 words (about 1 minute to read) and covers 12 key events in order, 4 characters, where and when it is set and 3 themes. Looking for the cast, ratings and where to stream it? See the movie page for UFO Robot Grendizer vs. Great Mazinger.

to read the plot summary
1 min
key events in the timeline
12
characters profiled
4
themes explained
3
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UFO Robot Grendizer vs. Great Mazinger (1976) movie poster
Released
Director
Osamu Kasai
Original language
Japanese
No spoilers

What Is UFO Robot Grendizer vs. Great Mazinger About?

The premise of UFO Robot Grendizer vs. Great Mazinger in 305 words, with nothing given away. The full story follows below.

In a world where towering machines of steel stand as monuments to humanity’s hope, a grand museum houses the legendary Megazord known as Great Mazinger beside its predecessor, Mazinger Z, both displayed as symbols of peace. The gleaming halls contrast with an uneasy quiet, hinting that even icons of protection can become coveted prizes in the eyes of distant forces. The atmosphere blends the awe of futuristic technology with a subtle, impending tension that hints at a storm gathering beyond Earth’s sky.

Duke Fleed, a lone pilot allied with the mighty Grendizer, carries the weight of his homeworld’s legacy while navigating the fragile balance of Earth’s new guardian role. His presence is both a bridge between alien heritage and human aspiration, and a promise of vigilant defense against threats unseen. Alongside him stands Koji Kabuto, the seasoned ace behind the original Mazinger Z, whose deep connection to the robot lineage infuses the narrative with seasoned courage and a reverence for the machines that have shaped history.

Above this delicate tableau, the alien forces of the Vegan Empire cast a shadow, their ambition focused on the formidable Great Mazinger now enshrined in the museum. A newly dispatched general from the empire captures Koji, learning the secrets of the robot’s power. This unsettling development hints at a precarious shift—what was once a beacon of protection could become a looming menace under foreign command. The tension between the guardians’ resolve and the empire’s designs sets the stage for a clash that threatens to ripple across the planet.

The tone of the story balances high‑octane super‑robot spectacle with the quieter, human moments of duty, camaraderie, and an unspoken promise to safeguard Earth. As the mysterious alien agenda unfolds, the stage is set for an epic confrontation where technology, honor, and the fate of the world hang in delicate balance.

Full plot

What Happens in UFO Robot Grendizer vs. Great Mazinger?

The complete story of UFO Robot Grendizer vs. Great Mazinger, from the first scene to the last, in 154 words (about 1 minute). Spoilers throughout. Names in the text link to 3 cast member pages.

Spoilers ahead

Barendos arrives on Earth and captures Duke Fleed’s closest ally, Koji Kabuto. While under mind control, Koji reveals the history and location of both Mazinger Z and Great Mazinger. King Vega seizes the opportunity to capture the Great Mazinger, and then forces Duke Fleed and his Grendizer to do battle against Great Mazinger. Grendizer and Great Mazinger clash in a tense confrontation until Grendizer manages to deactivate Great Mazinger using a special shot, suggested by Koji. In the fourth chapter (titled Terror of the Two Demons) of one Grendizer manga adaptation, Koji Kabuto and Tetsuya Tsurugi are mind controlled by a brain-wave machine created by Vegan Commander Depel. This attempt is countered when Boss Borot damages Gepel’s base and destroys the machine, ending the Mazingers’ rampage and preventing further city destruction. The chapter ends in a final battle between Mazinger Z, Great Mazinger, and Grendizer against Saucer Beast Zardan, with the heroes emerging victorious.

Timeline

UFO Robot Grendizer vs. Great Mazinger Timeline: Every Key Event in Order

12 key events in the order they happen, from “King Vega launches a special mission to Earth” to “Heroes claim final victory”. 11 events name a place, across 4 locations.

  1. 1

    King Vega launches a special mission to Earth

    King Vega orders General Barendos and his troops on a special mission to subdue Grendizer and conquer Earth. The plan sets them on a direct path toward the planet as the conflict escalates. The fate of Earth hangs in the balance as Vega’s forces prepare to strike.

  2. 2

    Barendos stops at Moonbase to issue warnings

    Before landing, Barendos stops at the Moonbase to warn the officials that if he succeeds they will be dismissed and killed. The warning underscores Vega's ruthlessness and foreshadows the consequences of the mission. It sets the stage for the Earth confrontation to come.

    When:Before landing Where:Moonbase

  3. 3

    Barendos arrives on Earth and captures Koji Kabuto

    Barendos lands on Earth and captures Duke Fleed’s closest ally, Koji Kabuto. While under mind control, Koji reveals the history and locations of Mazinger Z and Great Mazinger, arming Vega with crucial leverage for his assault.

    When:During capture Where:Earth

  4. 4

    Koji reveals Mazinger histories under mind control

    Under mind control, Koji divulges the history and locations of Mazinger Z and Great Mazinger, giving Vega strategic knowledge to target the hero machines. This information accelerates Vega’s plan to seize Great Mazinger and dominate the conflict.

    When:During captivity Where:Earth

  5. 5

    King Vega captures the Great Mazinger

    King Vega seizes the opportunity to capture Great Mazinger, securing a powerful weapon for his Earth assault. The capture narrows the heroes’ options and heightens the sense of danger for Duke Fleed and Grendizer.

    When:After Koji's confession Where:Earth

  6. 6

    Duke Fleed and Grendizer forced to fight Great Mazinger

    Vega forces Duke Fleed and his Grendizer to do battle against Great Mazinger. The forced confrontation puts the hero machines on a collision course, testing their resolve and abilities under duress.

    When:Immediate aftermath Where:Earth

  7. 7

    Koji's tactic hints at a deactivation shot

    As the clash unfolds, Koji's earlier insights hint at a tactic that could turn the tide: a special shot capable of disabling Great Mazinger. The idea introduces a tactical plan that could alter the battlefield balance.

    When:During battle Where:Earth

  8. 8

    Grendizer uses the deactivation shot to disable Great Mazinger

    Grendizer fires the deactivation shot and successfully disables Great Mazinger, halting its onslaught. The sudden turn of events shocks Vega’s forces and exposes a new vulnerability in their plan.

    When:During battle Where:Earth

  9. 9

    Fourth chapter manga note: mind control

    In the fourth chapter of a Grendizer manga adaptation titled Terror of the Two Demons, Koji Kabuto and Tetsuya Tsurugi are mind controlled by a brain wave machine built by Vegan Commander Depel. This subplot mirrors the peril faced by the Mazingers within the broader conflict. The chapter situates the same danger in a different medium.

    When:Fourth chapter Where:Manga adaptation

  10. 10

    Boss Borot defeats the brain wave machine

    Boss Borot damages Gepel’s base and destroys the brain wave machine, breaking the mind control that threatened the Mazingers. The intervention prevents further city-wide rampages and restores a measure of control to the heroes.

    When:During brain-wave incident Where:Gepel’s base

  11. 11

    Final triad battles Saucer Beast Zardan

    The chapter culminates in a battle between Mazinger Z, Great Mazinger, and Grendizer against Saucer Beast Zardan. United by necessity, the heroes overpower the alien threat and claim victory.

    When:Final battle Where:Earth

  12. 12

    Heroes claim final victory

    The Mazinger Z, Great Mazinger, and Grendizer emerge victorious against Saucer Beast Zardan, marking a conclusive win for the heroic machines. The battle ends with the Mazingers' triumph despite Vega’s complex schemes.

    When:Final battle conclusion Where:Earth

Characters

Who Are the Main Characters in UFO Robot Grendizer vs. Great Mazinger?

4 characters, among them Duke Fleed (Kei Tomiyama), Koji Kabuto (Hiroya Ishimaru) and Grendizer: who each one is and the part they play in the story. 2 of them link to the actor’s page.

  • DF

    Duke Fleed (Kei Tomiyama)

    Played by Kei Tomiyama

    Prince of Vega’s domain who pilots Grendizer to defend Earth. He is brave, strategic, and morally driven, often pushing for peaceful outcomes while taking decisive action when needed. His alliance with Earth’s defenders exemplifies a resolve to protect his new home.

    • 👑 Leadership
    • 🛡️ Valor
  • KK

    Koji Kabuto (Hiroya Ishimaru)

    Played by Hiroya Ishimaru

    Captured by Vega and subjected to mind control, Koji holds crucial knowledge about Mazinger Z and Great Mazinger. His revelations drive the battle’s turning points, while his personal autonomy becomes a focal point of resistance against control. He moves the heroes toward countering Vega’s strategy.

    • 🧠 Mind Control
    • 🧭 Knowledgeable
  • G

    Grendizer

    The colossal mecha piloted by Duke Fleed, instrumental in defending Earth against Vega’s forces. It engages in high-stakes battles with other robot giants and demonstrates the blend of brute force and precision typical of the series. Its power is central to turning the tide of combat.

    • 🤖 Mecha
    • 🛡️ Defender
  • GM

    Great Mazinger

    A rival mega-robot that initially clashes with Grendizer before being defeated by a strategic shot. Its presence increases the scale of the conflict and showcases the layered rivalry among Earth’s heroic machines. The battle emphasizes teamwork and tactical ingenuity.

    • 🤖 Mecha
    • ⚔️ Rivalry
Setting

Where and When Is UFO Robot Grendizer vs. Great Mazinger Set?

UFO Robot Grendizer vs. Great Mazinger is set in Earth and Moonbase. Here is why the place matters to the story.

When

Set in a space-age, retro-futuristic era where giant robots defend Earth from alien conquerors. The conflict unfolds across space and planetary surfaces, with bases and fleets clashing in spectacular battles. The timeline emphasizes high-tech warfare and interplanetary stakes typical of classic mecha sagas.

Where

Earth, Moonbase

The action shifts between Earth and a moonbase where command centers monitor Vega's invasion. Earth serves as the frontline for defense against the Vega empire. The moonbase functions as a strategic staging ground for fighter pilots and mecha operations.

  • 🚀 Sci-Fi
  • 🤖 Mecha
  • 🌍 Earth setting
  • 🌙 Moon base
Themes

What Are the Themes of UFO Robot Grendizer vs. Great Mazinger?

3 ideas the story keeps returning to, among them Conflict, Mind Control and Alliance.

  1. 01

    Conflict

    Earth's defense forces clash with Vega's invaders in a battle for control of the planet. The story centers on strategic duels between rival mecha and their pilots. Alliances shift as Koji Kabuto's fate influences the course of the war, and power struggles drive much of the action.

  2. 02

    Mind Control

    Mind control plays a critical role when Koji Kabuto is captured and brainwashed, exposing how control over key minds can alter the balance of power. The brain-wave technology is used to manipulate heroes and force confrontations. The theme explores manipulation, resistance, and the cost of hidden influence.

  3. 03

    Alliance

    Duke Fleed's Grendizer fights alongside other hero ships to defend Earth from Vega's empire. The narrative highlights unlikely partnerships formed in crisis, including shared strategies against common enemies. Despite rivalries, collaboration proves essential to counter a superior alien force.

Tone & mood

What Kind of Film Is UFO Robot Grendizer vs. Great Mazinger?

Tense in tone, with fast pacing and a straightforward story, going by the plot summary.

Tone
Tense
Pacing
Fast
Story
Straightforward
Intensity
High
Ending
Happy

A fast-paced and tense animated mecha battle where Earth's heroes face mind-controlled allies and alien threats, culminating in a triumphant, action-packed showdown to save the planet.

  • action-packed
  • tense
  • heroic
  • threatening
  • suspenseful
  • triumphant
  • alien invasion
  • mind control
  • mecha battle
  • rescue mission

Content notes: mind control, alien invasion, giant robot violence.

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FAQ

UFO Robot Grendizer vs. Great Mazinger Plot Questions

5 quick answers about UFO Robot Grendizer vs. Great Mazinger, taken from the plot summary, character guide and setting on this page and the film’s credits.

What is UFO Robot Grendizer vs. Great Mazinger about?

In a world where towering machines of steel stand as monuments to humanity’s hope, a grand museum houses the legendary Megazord known as Great Mazinger beside its predecessor, Mazinger Z, both displayed as symbols of peace.

Read the full plot summary

When and where does UFO Robot Grendizer vs. Great Mazinger take place?

UFO Robot Grendizer vs. Great Mazinger is set in Earth and Moonbase. Set in a space-age, retro-futuristic era where giant robots defend Earth from alien conquerors. The conflict unfolds across space and planetary surfaces, with bases and fleets clashing in spectacular battles.

The setting explained

Who are the main characters in UFO Robot Grendizer vs. Great Mazinger?

The story follows Duke Fleed (Kei Tomiyama) (played by Kei Tomiyama), Koji Kabuto (Hiroya Ishimaru) (played by Hiroya Ishimaru), Grendizer and Great Mazinger.

All the characters

What are the main themes of UFO Robot Grendizer vs. Great Mazinger?

The summary picks out 3 themes: Conflict, Mind Control and Alliance.

The themes explained

Who directed UFO Robot Grendizer vs. Great Mazinger?

UFO Robot Grendizer vs. Great Mazinger (1976) was directed by Osamu Kasai.

Osamu Kasai’s films

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