The Dragon Balls Are Stolen - S1.E10

Mai is able to fix Pilaf's dragon ball detector, and they see that Goku and his friends, with their six dragon balls, are on their way to Pilaf's castle to retrieve his dragon ball, the only one they don't have. Pilaf sends Mai and Shuu to meet them and steal their dragon balls, and they get all of them except the one Goku holds. Goku and his companions must then storm the castle to retrieve them.