The story revolves around the Z Fighters, a group of powerful warriors who protect Earth from various threats. The film begins with a brief history of the mystical artifact known as the Dragon Ball. It introduces a villainous character named Hoi, an eccentric wizard who seeks to resurrect the ultimate warrior, Tapion, in order to use his power to conquer the universe.
Hoi manages to gather all seven Dragon Balls and summons Shenron, the dragon deity who grants wishes. He requests the release of Tapion, who was sealed within a music box. The Z Fighters, including Goku, Vegeta, Gohan, Piccolo, and Trunks, sense a disturbance caused by Hoi’s actions and investigate.
Upon Tapion’s release, it is revealed that he is a powerful warrior from a distant planet called Konats, which was destroyed by a terrifying monster known as Hirudegarn. Half of Hirudegarn’s body was sealed within Tapion’s body, while the other half was trapped inside his younger brother, Minotia. Hoi’s true plan is to break the seal on Hirudegarn and unleash its destructive power.
The Z Fighters take Tapion under their protection, recognizing the threat posed by Hirudegarn. Tapion, initially reluctant to trust anyone, gradually develops a bond with Trunks due to their similar age and experiences. Meanwhile, Hoi manages to free the remaining half of Hirudegarn from Minotia, triggering a chain of events that sets the stage for an epic battle.
As Hirudegarn ravages the city, the Z Fighters engage in a fierce fight to protect the innocent. Despite their efforts, the monster overwhelms them, forcing Goku and his allies to retreat. Realizing the severity of the situation, Goku decides to combine his strength with the power of his companions through the technique known as the Fusion Dance.
Goku and Vegeta perform the Fusion Dance, resulting in the birth of the powerful warrior known as Gogeta. With their combined might, Gogeta confronts Hirudegarn head-on in an intense battle. The Z Fighters lend their energy to Gogeta, enabling him to deliver a devastating final blow, seemingly defeating the monstrous creature.
