Goku then meets Bulma of the Capsule Corporation, who was studying the five-star Dragonball until it was stolen by Mai and has invented a locator for the Dragonballs. Goku offers Bulma his protection in exchange for her help in finding Roshi. They ultimately track him down in Paozu City, and he joins them in their search. Under Roshi's wing, Goku begins training his ki, knowing that they must get all the Dragonballs before the next solar eclipse, when Ōzaru will return and join forces with Piccolo. In the midst of the group's search for the six-star Dragonball, they fall into a trap set by the desert bandit Yamcha, but Roshi convinces Yamcha to join by promising a portion of the royalties for Bulma's invention. Together, the group fight off an ambush by Mai and successfully acquire the next Dragonball.