Dragon Ball Z is about a man named Gokou, who is very strong and but not very smart on how the world works. In the begginning a ferice fighter named Raditz from another planet lands on earth and starts destroying things. He starts looking for his brother that was sent there as a baby with a mission to get rid of all human life. But as he sees his brother has not done his job. Raditz seeks out the most powerful person on earth only to discover that it is his brother who has become earths greatest defender. Some words are exchanged between the 2 and Raditz finds out that as a kid his brother Kacarot who goes by the name Gokou now, hit his head and lost his memory of being a Saiyan and there for does not know that he is to destroy a human life. Raditz gets mad at Gokou and kidnaps his son Gohan. Raditz tells Gokou that he has till morning to kill 100 humans or he will kill his son. Gokou does not know what to do, untill his arch rival Piccolo shows up. They decide to join forces untill the threat to earth is over. They use the bleaper which is used to find Dragon Balls to search for Gohan which has one sowen to the top of his hat. When they find Raditz a fight ensues and Raditz kicks their butts really hard, but just when things are starting to look really bad for the 2 hereos Gohan powers up freaking Raditz out really bad cause Gohan's powers are higher then his and his scanner never detected it. Gohan jumps out of Raditz's pod (which he was being held in) shattering it into lots of little pieces and then attacks Raditz and head butts him in the chest, cracking Raditz's armor. Raditz recovers quickly and decides to finish Gohan off first cause he poses a greater threat then Gokou and Piccolo combined! Raditz starts kicking Gohan around and Gokou get mad and remembers about a weekness that he had before he had his tail removed. Gokou gets behind Raditz just as Raditz is about to hit Gohan with a beam of energy when Gohan grabs Raditz's tail and squeezes. Raditz is brought to his knees begging for Gokou to let go. He says that he will leave earth and never come back, Gokou not knowing a lie when hes told one even when Piccolo tells him that Raditz is lying, belives Raditz and lets him go. Raditz takes advanatage of this and knocks the wind out of Gokou. More fighting goes on and Gokou eventually get Raditz into a full nelson and tells Piccolo to use his beam cannon to destroy Raditz. Piccolo seeing a chance to take out 2 rivals at once lightly protests saying that it will kill him too, but Gokou being the person he is, says he doesen't care as long as the earth is is safe. So Piccolo powers up his beam cannon fires it. It goes through Raditz killing both him and Gokou.