In the movie, the Z Fighters face a new threat that starts with the burning of a forest, caused by the impact of a cosmic object, in which Son Gohan and Kuririn rescue the forest animals and a small dragon named Icarus. Although they are able to restore the forest to its normal state with the Dragon Balls, Icarus does not return and stays with Gohan, much to Chi-Chi's fury. Son Goku then shows a nearby cave to let Gohan keep the dragon with him. Later, the cosmic object that crashed and caused the forest fire earlier reveals itself to be a probe, and shortly thereafter, the Earth is visited by an unfriendly group of aliens under the leadership of a Saiyan. Upon arriving, they plant a seed which grows the Tree of Might, a plant that sucks the life of the planet on which it was planted and leaves it a desert. At King Kai's request, Goku, Kuririn, Yamcha, Tien, and Chaozu investigate and try to destroy the Tree, but they are unsuccessful. They are then confronted by the aliens whilst their leader watches from inside the spaceship. Eventually, Kuririn, Yamcha, Tien, and Chaozu are defeated by the aliens, with only Goku remaining as the one who can hold his own against them.
During the ensuing battle, Chaozu is rescued by Gohan, who had just arrived, and demonstrates his incredible fighting skills by easily taking out Lakasei. He is then encountered by the aliens' leader Tullece, a Saiyan who bears a striking resemblance to Goku. Tullece gives Gohan a choice to either join him or die. Gohan refuses to join Tullece, and is saved in time thanks to the arrival of Piccolo. However, Tullece ambushes and blasts him from behind, having Gohan where he wants him. He notices Gohan's regrown tail and creates an artificial moon, forcibly turning Gohan into a Great Ape and sets him on Goku, who is almost crushed to death in Gohan's hand until Icarus arrives and calms Gohan down.
But when Tullece attacks Icarus, Gohan is angered and turns on Tullece, who fires an attack at Gohan. Before the attack can make contact, Goku manages to cut his son's tail off and restore him to normal. Cradling the little one in his arms, Goku promises to defeat Tullece. Tullece's henchmen attack Goku, who uses the Kaio-ken and makes quick work of them while Piccolo unsuccessfully fights Tullece again. Goku and Tullece then fight, with Goku having the upper hand, until Tullece pushes his power further by eating a fruit from the Tree of Might. With his new power, Tullece dominates Goku and beats him to the point that he is no longer able to fight, even with the use of the Kaio-ken x10 (x20 in the English version).
Slowly recovering while Tullece is distracted by the rest of the Z Fighters, whom he dispatches of, Goku decides to use the Spirit Bomb. Despite gaining energy from the living, he is not able to attack Tullece as he counterattacks with the Calamity Blaster, neutralizing Goku's Spirit Bomb. Unable to gather more energy from living beings, Goku decides to steal energy from inside the Tree of Might itself. Eventually successful in creating the Spirit Bomb, Goku fires it at Tullece, who tries to counter with his own ki wave. He is carried up the trunk of the Tree of Might and destroyed along with the Tree when the Spirit Bomb explodes. With the terror now over, the Z Fighters return to their normal lives once again.
- Masako Nozawa as Son Goku, Son Gohan, & Tullece
- Mayumi Tanaka as Kuririn
- Toru Furuya as Yamcha
- the late Hirotaka Suzuoki as Tien
- Hiroko Emori as Chaozu
- Toshio Furukawa as Piccolo
- the late Hiromi Tsuru as Bulma
- Mayumi Sho as Chi-Chi
- Naoki Tatsuta as Oolong & Icarus
- Naoko Watanabe as Puar
- the late Kohei Miyauchi as Master Roshi
- Joji Yanami as King Kai & the narrator
- the late Kenji Utsumi as Shenlong, Lakasei & Rasin
- Yuji Machi as Daiz
- Shinobu Satouchi as Cacao
- Banjo Ginga as Amond
- Sean Schemmel as Goku & King Kai
- Stephanie Nadolny as Gohan
- Sonny Strait as Kuririn
- Christopher Sabat as Yamcha, Piccolo, Icarus & Shenlong
- John Burgmeier as Tien
- Monika Antonelli as Chaozu & Puar
- Tiffany Vollmer as Bulma
- Cynthia Cranz as Chi-Chi
- Brad Jackson as Oolong
- Mike McFarland as Master Roshi
- Robert McCollum as Rasin & Lakasei
- Mark Lancaster as Daiz
- Jeff Johnson as Cacao
- Paul Slavens as Amond
- Chris Patton as Tullece (spelled Turles in the U.S)
- Shane Ray as Great Ape Gohan
- Kyle Hebert as the Narrator
- This marks real famous Japanese voice actress, Masako Nozawa's, first time playing three different characters in a DBZ film (Goku, Gohan and Tullece). She has been apart of the Dragon Ball Franchise since 1986, when she was known for playing Goku as a child.
- This film marks Mayumi Sho's final performance as Chi-Chi. But her real final performance as Chi-Chi is in DBZ Season 2, and in the video game Dragon Ball Z Budokai. As of Dragon Ball Z Season 3 - Present, her voice actress successor for her roles as Chi-Chi and Puar is Naoko Watanabe.
- The power levels reported by Turles' scouter are: Gohan - 10,000, Piccolo - 18,000, Goku - 30,000. They are a lot higher than the power levels reported by Vegeta's scouter in the Saiyans Saga.
- Goku is shown holding his Power Pole on the film poster, even though he does not use it in the film.
- The animation in the opening theme is part of the movie itself, as it shows the gathering of the Dragon Balls by Gohan and his friends to restore the forest. The "Rock the Dragon" opening for the FUNimation English version of Dragon Ball Z uses footage mostly from this movie.
- This is the first theatrical appearance of King Kai in a movie, though his techniques (Kaio-ken and Spirit Bomb) debuted in the previous movie. This is also the first appearance of Yamcha, Tien, and Chaozu in a Dragon Ball Z movie; though Yamcha had appeared in all three Dragon Ball movies, and Tien and Chaozu also had first appeared in the third Dragon Ball movie.
- This is the only movie in which Yamcha wears a gi with the Turtle School symbol on the front and the King Kai symbol on the back. His gi of choice after being resurrected in the series is the opposite (King Kai front, Turtle back).
- In one scene of the movie, there is a Ferris Wheel that says D.B.Z.
- If this film does indeed take place during the three-year wait for the androids as some fans speculate, it is inconsistent that Gohan first meets and names Icarus in this film, whereas he already knew the young dragon in the Garlic Jr. saga.
- The 12th Shunsuke Kikuchi music package for the franchise starts here. The cues were designated "M10XX" codes, and this package would make its "first" debut in Bardock: The Father of Goku, followed by its "official" debut in Goku's New Power.
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