Pilaf and The Mystery Force

Goku stops at a lake for a swim. When he gets out, he finds that the dragon radar has been stolen. He picks up on the thief's scent and follows it to its source. The thief tells him that he sold the radar to an antique salesman in a nearby town. Goku locates the shop and finds his dragon radar there. He picks up a signal coming from the shop, so he turns around and sees Emperor Pilaf and Mai holding the four-star ball, having just bought it from this store. They are able to escape on their ship, but Goku follows them on the Nimbus Cloud. Back at the antique store, a mysterious military force has arrived looking for a Dragon Ball. The salesman gives them a four-star ball, but they recognize it as a fake. Pilaf's four-star ball was also a fake, but Goku doesn't yet know. The signal he picked up on was the six-star ball in a nest above the shop. A bird then flies away with the ball in its talons.