The planet Cybertron faces total annihilation from a massive Grand Black Hole, forcing Galaxy Convoy, the supreme commander of the Autobots (called Cybertrons in Japan), to order an emergency evacuation to Earth. As the Autobots prepare to leave, the ancient time-space guardian Vector Prime appears with a dire warning: the only way to seal the black hole and save the universe is to gather the four mythical Planet Forces. These artifacts were created from the spark of Primus, the Transformers god, and are lost across the galaxy. Before Vector Prime can elaborate, the Decepticon (Destron) Emperor of Destruction, Master Megatron, attacks and steals the map revealing the Planet Forces locations, launching a new race across the cosmos.

The story follows Galaxy Convoy and his team, including the sincere vice-commander Dreadlock, the hot-headed speedster Excillion, and the veteran warrior Guardshell. They are joined on Earth by three human teenagers: the mechanically gifted Coby, his younger sci-fi enthusiast brother Bud, and the city girl Lori. While the Autobots disguise themselves as Earth vehicles to remain hidden, they befriend the children who become crucial allies in their mission. The Decepticons are led by the power-hungry Master Megatron, accompanied by his ambitious and treacherous minion Starscream and the brawling Thundercracker. The mysterious Vector Prime also brings small, curious robots called Microns who enjoy interacting with the human children.

The narrative spans multiple unique worlds, each home to a Planet Force. The first is the speed-obsessed planet Speedia, where the key is the grand prize in a racing tournament. Next is the beast-mode ruled planet Animatros, where Jungle Planet's dictator Scourge hoards another key. The search leads back to Earth for its hidden key and finally to the lost, colossal planet Gigantion. As the Autobots race from world to world, befriending local leaders like Nitro Convoy and Flame Convoy, they must overcome Megatrons schemes and Starscreams betrayals. A notable arc involves the Autobots combining their powers, such as Galaxy Convoy merging with the aerial warrior Wingsaber, to face increasingly powerful threats like a super-charged Starscream.

The manga follows the major story beats of the Galaxy Force anime but in a more abbreviated form. Due to the series being canceled prematurely after nine installments in Comic Bom Bom, the manga ends with an "open" conclusion. It finishes on a dramatic double-page spread showing Optimus Prime and Wingsaber defeating the super-powered Starscream. This abrupt ending means the narrative does not cover the final arcs involving the rescue of Gigantion, the revelation of the mysterious Planet X, or the climactic final battle against a transformed Master Galvatron, leaving the overarching quest incomplete.