"A Discovery" (ブルマからの知らせ Buruma kara no Shirase, lit. "Bulma's News") is the one hundred sixty third chapter of Dragon Ball Z and the three hundred fifty-seventh overall chapter of the Dragon Ball manga.
On the airplane to Kame House, Krillin relates to Yamcha, Gohan, and Chi-Chi how powerful the new androids are, saying that killing Goku is a game to them. Yamcha asks what they should do, and Krillin admits he has no idea. Future Trunks suggests that he go even farther back in time using his Time Machine and destroy the androids before they are activated, since they now know where Dr. Gero's Lab was. Yamcha thinks this is a good plan, but Krillin asks if he can get back to the future after going further into the past, as the Time Machine takes a long time to charge up. Gohan asks if the current androids would simply disappear, and Future Trunks realizes that only the timeline he would travel to would be affected. Krillin is confused, and Future Trunks explains that each trip to the past creates new futures, using their situation as an example. Yamcha and Krillin then ask what the point of Future Trunks' trip to their timeline was, and Future Trunks says that he was hoping to find the androids' weakness or bring Goku to his timeline. He notes that this timeline is different, and Gohan asks why. Future Trunks says he does not know, but Chi-Chi says not to worry, as his trip has saved Goku's life. The others agree that things will turn out for the best.
Meanwhile, Vegeta, still incensed over losing to Android 18, is training alone in the mountains. He turns Super Saiyan and destroys the nearby rock formations with just his power. He says that a Super Saiyan is supposed to be invincible, and wonders how he was defeated, as he should be the strongest in the universe. He vows to surpass the androids, and then to defeat Goku. Meanwhile, the androids are still driving in the Lucky Foods van. 18 asks Android 17 if he knows where Goku's House is, and 17 says they will find something eventually. Android 16 then chimes in with the house's coordinates, and says they can be there in a few minutes if they fly. 18 agrees with flying there, but 17 says that small things in life are what make it fun.
Back on the Capsule airplane, Krillin is chosen to call Bulma and tell her what has happened. Krillin complains, telling Future Trunks that his mother always bites people's heads off, and Future Trunks says that she is the same in the future. Krillin then calls Bulma, who immediately yells at him for not having called sooner. Bulma asks where they are and if Future Trunks is there. Krillin replies that he is, and Bulma tells him to put Future Trunks on. Bulma relates to Future Trunks how a farmer found a strange Capsule Corporation vehicle out in the wilderness, and asked for the company's help to operate it. Bulma says that they did not recognize the man's description, so they asked for a photo, and that the vehicle is in fact Future Trunks' Time Machine, only wrecked. Future Trunks is stunned, saying that he has his Time Machine with him in capsule form. Bulma tells Future Trunks that the Time Machine in the photo is covered with moss and looks old, and asks how many she made in the future. Future Trunks says that she was barely able to make one, and Bulma decides to fax Trunks the picture. She does so, the picture shows Future Trunks' Time Machine damaged and covered in moss, which stuns Future Trunks.