The Namek Saga was the second Saga in Dragonball Z. The Namek Saga is one of the longest sagas in Dragonball Z and has from when Vegeta is beaten to when Goku arrives on Namek. I have a list of the episodes and a summary of everything that happens in it. The Namek Saga has episodes 27-53 in it.
As Goku is rushed to a hospital, it's revealed that the Dragon Balls on Earth are now powerless due to Piccolo's demise. The only hope to bring back the dead heroes is to fly to Planet Namek for the original Dragon Balls. Headstrong and technically-talented as always, Bulma rushes forward, devising a way to use an ultra-fast space craft to reach Namek. Bulma, Krillin and Gohan are off to Planet Namek.
But they are not the only ones after the Dragon Balls. Vegeta returns to Frieza Planet #79 to regenerate himself using a special medical tank. He discovers that his former boss turned enemy, Frieza, has already left for Namek after the Dragon Balls. Vegeta rushes off to Namek to find the Dragon Balls for himself.
Soon, Vegeta, Frieza, and our heroes are on Namek searching for the seven Dragon Balls. There is one Dragon Ball per Namek village, each ball being protected by the village elder. Frieza has an entourage of minion monsters which terrorize the villages, eventually gaining four Dragon Balls.
En route to Namek, Gohan, Krillin and Bulma run into one of the many dangers of space: an alien warship. Caught offguard, they are ambushed as they investigate the alien ship. Fortunately for our friends, the ship enters an asteroid belt. Bulma jumps to the rescue and steers the ship out of harm. The aliens, who are actually refugees looking for a new home because Frieza destroyed their planet, realize Gohan, Krillin and Bulma mean them no harm. They reveal a shortcut to Namek and wish their new friends good luck.
Taking the shortcut, Gohan, Krillin and Bulma reach the planet Namek long before they had expected. This is great... assuming the planet is really Namek. It appears like the planet they were expecting, and the inhabitants do look like Namekians. These inhabitants are helpful to our friends as they encounter giants, volcanoes, ice caves, and assorted dangers in their search for Dragon Balls.
But that's nothing compared with the real danger our heroes are facing. Their Namekian helpers Raiti and Zaacro aren't Namekians at all. They are aliens stranded on this deserted planet. Anxious to escape and masters of illusion, Raiti and Zaacro are willing to do anything to grab a spaceship and leave this planet behind. They have read Gohan, Krillin and Bulma's minds, and concocted the environment they were expecting to find, secretly making plans to steal their spaceship and leave our friends stranded. They almost succeed, but don't know the secret password to open the door to the ship. At the last minute the tables are turned, and Gohan, Krillin and Bulma zoom off in their spaceship toward the true planet Namek.
Things are not going so well on planet Namek. Frieza is terrorizing the villages and collecting the Dragon Balls. How will Gohan, Krillin and Bulma ever bring their friends back if Frieza gets the Dragon Balls first? More importantly, what chance does the universe have if Frieza collects all seven Dragon Balls and realizes his wish for immortality?
To make matters worse, Vegeta is on Namek and stronger than ever after his near fatal injuries on Earth. Saiyans have the unusual ability to reach higher power levels after healing from serious wounds. Vegeta is seriously injured again in a fight with Zarbon, one of Frieza's henchmen. He is left to die until Frieza tells Zarbon to bring Vegeta to him, or else. Vegeta has hidden a Dragon Ball and is the only one who knows its location.
Meanwhile, Frieza has decided to summon the elite fighters known as the Ginyu Force to help search the planet for Dragon Balls and take care of any problems that might develop. They will arrive in five days. Goku has been summoned and is on his way to Namek, traveling in a specially constructed spaceship with special training facilities. Help is on the way, but time is running out for our heroes.
Krillin is taken to Guru's house. Guru is the Eldest, the leader of all the Namekians and the creator of the Namekian Dragon Balls. He is, unfortunately, very ill. If anything happens to Guru, the Dragon Balls, which the good guys need to bring their allies back to this dimension, will cease to exist. Gohan, Krillin and Bulma must collect these Dragon Balls while Guru is still alive. This seems impossible since Frieza already has five of the Dragon Balls. But the good guys won't give up.
Guru lays hands on Krillin, realizes that he is good at heart, and decides to give his Dragon Ball to Krillin for safe keeping. Now atleast Frieza can't get all seven - not as long as Krillin has one of them. Guru also awakens the sleeping power with Krillin, giving him more power than ever!
Frieza's plan backfires. He has Vegeta brought to his spaceship so he can learn where Vegeta's Dragon Ball is hidden. But Vegeta makes a daring escape from Frieza's spaceship prison, stealing the five Dragon Balls, which were in Frieza's possession.
Vegeta locates Krillin and Bulma and realizes they have a Dragon Ball (the one given to Krillin by Guru). Vegeta promises to spare their lives in exchange for the ball. Krillin reluctantly hands over the ball in order to save Bulma's life.
Suddenly Zarbon, Frieza's minion, arrives and transforms into the uglier version of himself, giving him increased strength to battle Vegeta. But Vegeta's previous battle has made him even stronger, allowing him to defeat Zarbon. Vegeta takes Krillin's Dragon Ball and flies off, surprisingly keeping his promise not to kill Krillin and Bulma. Gohan returns with the Dragon Ball that was hidden underwater. Now Vegeta cannot make his wish for immortality.
Back on Earth, Yajirobe visits Goku in the hospital and gives him a Senzu bean. Goku immediately recovers and goes to the Capsule Corporation. Dr. Brief has designed a ship that will allow Goku to train at up to 100 times Earth's gravity. Goku takes off for Namek.
Krillin takes Gohan to have his hidden powers revealed by Guru. On the way, Vegeta catches up with Krillin and offers a temporary alliance. Vegeta claims his wish for immortality is their only chance of beating the "unbeatable" Ginyu Force, which he senses has just arrived. Gohan and Krillin reluctantly agree, but it is too late as the Ginyu Force shows up for the Dragon Balls.
The Ginyu Force (Captain Ginyu, Jeice, Burter, Recoome, and Guldo) retrieve the seven Dragon Balls. Captain Ginyu flies off to deliver the Dragon Balls to Frieza, and the remaining members stay to finish off Vegeta, Gohan, and Krillin.
Guldo, who has the ability to freeze time by holding his breath, torments Krillin and Gohan. Right as they are about to be speared by trees, Vegeta steps in and saves them by chopping off Guldo's head.
Recoome is up next. He easily brings Krillin, Gohan, and Vegeta to the brink of death.
Goku gives Gohan, Krillin and Vegeta Senzu Beans, and then effortlessly defeats Recoome. Gohan, Krillin and Vegeta all marvel at the extreme power Goku possesses. Burter and Jeice begin to attack Goku, but he doesn't seem at all concerned with the two members of the Ginyu Force.
Vegeta senses something has changed in Goku - "Did he become a legendary Super Saiyan!?"