The planet of New Namek is under attack by a massive metal planet and lethal robots, prompting the Guardian of Earth, Dende, to reform the Earth's Special Forces to save his people. The Z Warriors, unaware of what to expect, discover that the invasion is led by Koola, Frieza's older brother, who Goku supposedly killed long ago.

Dragon Ball Z: The Return of Cooler
Goku and his allies embark on a perilous mission to liberate the enslaved population of New Namek from the tyrannical grasp of Cooler, a cyborg who has miraculously revived.