Dr. Lychee may be the last of the Tuffle people, a race that was completely wiped some time ago by the Saiyans. He now plans to take revenge on the remaining Saiyans, Goku, Vegeta, Trunks, and Gohan. He creates a machine that will emit Destron, a gas that could destroy all life on Earth. The Saiyans, plus Piccolo, only have 72 hours to destroy these machines and find Dr. Lychee. When trying to destroy the final machine, Vegeta discovers that it is protected by an impenetrable energy barrier. Frieza, Cooler, Turles and Lord Slug appear and engage the heroes one on one. The heroes continue to lose against their foes. It is revealed that these ghost warriors are made of Destron gas and cannot be beaten unless the gas is neutralized. The barrier is destroyed by Bulma, who also came with the antidote for the Destron gas. She then manages to stop the gas. The heroes kill Frieza and the others. The heroes track down Dr. Lychee on the Dark Planet and engage him, discovering that his ghost warriors are generated by a machine called Hatchiyack, a device powered by the Tuffles' hatred for the Saiyans. It is also revealed that Dr. Lychee is a ghost warrior himself, generated by Hatchiyack. When Vegeta vaporizes Lychee, preventing him from re-materializing, the hate of the last remaining Tuffle causes Hatchiyack to exceed its limit. Hatchiyack appears in a powerful android body, whose power is said to match or perhaps even exceed that of Broly, according to Goku. Hatchiyack devastates the heroes until the Saiyans (after having transformed into their Super Saiyan states) and Piccolo combine their powers together into one massive wave of energy, ending the threat of the Dr. Lychee. At last Goku, Vegeta, Gohan, Trunks and Piccolo return to Earth just as the Dark Planet explodes.