The Frieza saga covers the massive battle with Frieza it goes on for a long time with nearly all of Earth's special forces trying to fight Frieza. It covers Goku's transformation to a Super Saiyan and all of Frieza's, it has episodes 61-92 in it.
With the future of the Planet Namek at stake, Guru sends Dende to find Krillin and Gohan and give them the all-important password. Frieza arrives at Guru's and is met by some Namekian warriors. Frieza kills all but Nail, then goes in to Guru to find out how to call the Dragon. Frieza is about to kill Guru, but Nail explains that if Guru dies, the Dragon Balls are unusable. To buy time for Dende to call the Dragon, Nail leads Frieza off to a remote area to fight. Frieza learns that fighting Nail is a trick to stall him, and races off to his ship.
Dende finds Krillin and they head to Frieza's ship to summon the Dragon. Vegeta is sleeping, and awakens to find the Dragon already summoned. Piccolo has been brought back to life as the first wish, and then teleported to Namek for the second wish. Vegeta wants the third wish to ask for immortality, but just as Dende is asking, Guru dies and the Dragon Balls turn to stone. Vegeta's wish is not granted, and to top it all off, Frieza shows up furious that the Dragon has been summoned.
Gohan is furious at Piccolo's death and powers up. His hidden powers are revealed as he takes on Frieza. Gohan is too much for Frieza, so he transforms into his final form. While Frieza transforms, Dende heals Piccolo. Dende also reluctantly heals Vegeta.
Frieza sees the usefulness of Dende's healing, so the first thing he does after he transforms is eliminate Dende. He also tries to blast Gohan, but Vegeta is quick and saves Gohan. Vegeta and Frieza fight, and Vegeta is no match. Goku shows up and Vegeta is rescued, but not for long. Vegeta tells Frieza that Goku is the legendary Super Saiyan that will kill him. Frieza gets angry and blasts a hole through Vegeta's heart. As Vegeta dies, he asks Goku to take vengeance for all Saiyans. Vegeta is buried and Frieza and Goku begin to fight.
Goku and Frieza are still at it. Frieza boasts he can win using just 50% of his power. Goku is losing. In a desperate attempt, Goku prepares a Spirit Bomb. Piccolo steps in to buy time for Goku to finish gathering power. The Spirit Bomb crushes Frieza, but he survives.
The Ginyu Force shows up on King Kai's planet. They were invited there by King Kai to fight Tien, Chaiotzu and Yamcha, who have been training. On Earth, Chi-chi, Yajirobe, Oolong, and Master Roshi were preparing to take off for Namek, but their ship breaks down before take off.
Goku and Frieza continue to fight. Frieza is angry he is having to use so much of his power to fight an "inferior monkey". Frieza blasts a huge fireball at the core of Planet Namek. If he can't beat Goku, he'll blow up Namek instead. Planet Namek is starting to break up, and will explode in 5 minutes. Goku is in trouble and Gohan steps in. When Goku reappears he tells Gohan to leave Namek.
Back on Earth, Kami and Popo have gathered the Dragon Balls. With King Kai's help, they are able to devise a plan to bring back all those killed by Frieza. This will bring back Guru, and in turn the Namekian Dragon Balls. The wish is made on Earth to bring back all killed by Frieza. King Kai then telepathically asks Guru to wish all those on Namek, except Goku and Piccolo, back to Earth. Dende makes the wish, and all are teleported to Earth.
Now on Earth, Dende heals Piccolo, and realizes that he had merged with Nail. Guru, also on Earth, is dying. Guru transfers his role as Senior Elder to Moori, another Namekian, so that the Namekian Dragon Balls will not die with him.