Piccolo and Gohan arrive and square off against Slug’s goon squad, only to be defeated. All hope seems lost, until Krillin show up, and they easily defeat Slug’s men. With all his men defeated, Lord Slug emerges and Krillin challenges him, only to lose in one punch. Goku battles Lord Slug, but quickly loses the advantage, being no match for Slug’s power. When Lord Slug finally decides to finish Goku with the final punch, Goku retaliates by catching it and his anger explodes, causing him to turn into a Giji Super Saiyan (which is misinterpreted as an actual Super Saiyan in the movie, causing it get its name Giji Super Saiyan, meaning False Super Saiyan).
In a flash of powerful blows, Goku completely crushes Lord Slug’s arm and when it seems Goku is about to win, Slug reveals his Namekian heritage, ripping off his broken arm and regenerating a new one. The shock then regresses Goku back to his normal state and before his eyes Lord Slug transforms into a gigantic version of himself. Slug regains the advantage but before he is able to finish Goku off, Piccolo remembers the Namekian weakness: their sensitive hearing (revealed in the beginning of the movie). He then orders Gohan to whistle again and before Gohan can do so, he immediately rips off his own ears to protect himself from the disturbing sounds. Slug is immediately caught off-guard, saving Goku.
Piccolo then gives all his energy to Goku and with his power regained, Goku uses the Kaioken attack to knock down Slug long enough to create a Spirit Bomb. Goku then hurls the powerful energy sphere at the Namekian tyrant, easily destroying him. With the villains defeated, the heroes celebrate over their victory. The movie ends with Master Roshi waking up from his nap, wishing something interesting had happened.