"Dragon Ball Z: Plan to Destroy the Saiyajin" is a special anime feature that expands on the lore of the Dragon Ball Z universe. The narrative centers around Dr. Raichi, a vengeful scientist from the extinct Tuffle race, who harbors deep resentment toward the Saiyans for their role in the destruction of his people. Using advanced technology, Dr. Raichi creates a powerful artificial being called Hatchiyack, designed to exact revenge on the Saiyan race. Hatchiyack is a bio-mechanical weapon capable of evolving and growing stronger through combat, making it a formidable adversary.

The story unfolds as Dr. Raichi activates Hatchiyack and sends it to Earth, where the remaining Saiyans, Goku, Vegeta, Gohan, and others, reside. Hatchiyack begins its mission by attacking the Z Fighters, forcing them to confront this new threat. The battles are intense, with Hatchiyack demonstrating its ability to adapt and overpower the Saiyans. The Z Fighters must rely on their combined strength and strategic teamwork to stand a chance against the relentless machine.

As the conflict escalates, the narrative delves into the history of the Saiyan-Tuffle war, providing context for Dr. Raichi's motivations and the creation of Hatchiyack. The story also explores themes of vengeance and the consequences of past actions, as the Saiyans are forced to confront the legacy of their ancestors' destructive actions. The climax of the story features a dramatic showdown between the Z Fighters and Hatchiyack, with the fate of Earth and the Saiyan race hanging in the balance.

The main characters include Goku, Vegeta, Gohan, Piccolo, and other members of the Z Fighters, each contributing their unique abilities to the battle. Dr. Raichi serves as the primary antagonist, driven by his desire for retribution, while Hatchiyack embodies the physical manifestation of his hatred. The narrative maintains a focus on action and conflict, with the Z Fighters' resilience and determination being central to the resolution of the story.