About Dragon Ball Z Kai
The last descendants of an evil race of warriors known as the Saiyans are on a collision course with Earth, and Goku, the strongest fighter on the planet, is all that stands between humanity and extinction. To save his friends and the world he loves, Goku must travel to a realm from which few return, but should he survive, he'll discover the power to face the villainous Saiyan warlord, Prince Vegeta.
Scattered and hidden in different parts of the world are seven mystical objects known as the Dragon Balls. When the seven Dragon Balls are gathered together, they can be used to summon a dragon named Shenron who can grant a single wish. Goku and his friends have made use of the Dragon Balls' wishes in the past to do good, but there are those who seek to use them for their own evil plans.