Keychain | Dragon Ball | Dragon Balls

The Dragon Balls themselves are seven magical orbs which are scattered across the world. When assembled, they can be used to summon Shenron, the dragon who will grant one wish within its limit. After the wish is granted, the Dragon Balls are scattered again across the world and become inert for one year. In times past, it would take generations to search the world and gather the Dragon Balls. At the beginning of the story, however, a 16-year-old genius girl named Bulma invents a Dragon Radar to detect the Dragon Balls and makes the process far easier than it was originally intended to be.

Dragon Ball  (from Dragon Ball Wiki)
The story of Dragon Ball follows the life of Son Goku, a monkey-tailed boy loosely based on the traditional Chinese folk tale Journey to the West, from his life and adventures as a child all the way up to being a grandfather. During his life, he fights many battles and eventually becomes (arguably) the strongest martial artist in the universe. He is not without help, however: the comic boasts a large ensemble cast of martial artist heroes and villains which provide the conflict that drives the story.
A unifying component of the plot accompanying Goku's progression as a martial artist is his search for the eponymous Dragon Balls. They are one component of the universe, but are not the focus of most of the plot lines of the title.