"The Lost Dragon Ball" (最後の龍球 Saigo no Doragon Bōru, lit. "The Final Dragon Ball") is the ninety-seventh chapter of the Dragon Ball manga.
After single-handedly defeating the Red Ribbon Army, Goku tries to use the Dragon Radar to locate the remaining Dragon Ball, but is surprised when he learns that it does not appear on the radar. Meanwhile, Yamcha lands the airplane a distance. Muten-Rōshi stops them from rushing in, saying they need a plan, and Oolong pretends to have a stomachache to get out of going in. They bicker as they try to plan how to enter, when Kuririn tells them to get down, as something is flying towards them. Puar quickly changes the plane back into a capsule and they all hide. They then notice that the figure appears to be Goku on the Flying Nimbus. Goku, meanwhile muses that the Dragon Radar is broken and wants to have Bulma fix it, but he does not exactly know the way back. The others call out for him and catch his attention, and he flies down to them. They initially think Goku has given up on invading them, but they are all shocked to learn that Goku invaded and defeated them on his own, obtaining six Dragon Balls. Goku asks Muten Roshi if his Grandpa Gohan climbed Korin Tower too, and Roshi is amazed to discover that Goku climbed up Korin Tower on his own, concluding that this is how Goku got so much stronger. Goku asks Bulma to fix the Dragon Radar, and Goku explains that he is gathering the Dragon Balls to resurrect Bora, the father of his friend Upa. Bulma agrees to but says she cannot fix it out there, so they fly to the Kame House. During the flight they all ponder Goku's newfound strength, and Muten Roshi believes that Goku will only get stronger and stronger.
Back at the Kame House, Bulma has opened up the Dragon Radar and discovers that not one part of it has been broken. Goku points out that it showed all seven Dragon Balls before, and Bulma concludes that something might have swallowed it. She explains that if its electromagnetic waves are surrounded by a living being, the radar will not pick it up. Goku is about to give up, when Muten Roshi tells them they can go to see Fortuneteller Baba, as she will surely be able to locate it. Bulma decides that she wants to go home, and Oolong does not want to go either, so Yamcha, Puar, Kuririn and Goku will make the journey. They set off on the plane to find Fortuneteller Baba and locate the last Dragon Ball.