"A Sound of Thunder" (トランクスの疑惑 Torankusu no Giwaku, lit. "Trunks' Suspicion") is the one hundred fifty third chapter of Dragon Ball Z and the three hundred forty-seventh overall chapter of the Dragon Ball manga.
Seeing Android 19's head lying on the ground, Future Trunks says that this is not right, and wonders what is going on. Just then he sees an explosion at the site of battle, and flies off towards it. As he flies, he notes that Android 19 is not one of the androids he knows, and wonders if there are now three. Back at the battle, Piccolo is still easily handling Android 20, who wonders how Piccolo exceeded their calculations. Piccolo says that regardless of whether the androids were not as strong as expected or the Dragon Team became too strong, the future has now been changed. Tien Shinhan says that he does not like Piccolo and Vegeta being so powerful, but that it is good for the moment. Vegeta tells Piccolo to finish Android 20, and Piccolo says that he will, as he is not soft like Goku.
Just then everyone senses a ki approaching, and Future Trunks arrives on the scene. Piccolo calls him by name, and Vegeta realizes that Future Trunks is his son from the future. Trunks notes that he does not recognize Android 20 either, and Android 20 wonders who Trunks is. He decides to return to his laboratory, thinking that he has miscalculated too much. Trunks asks who Android 20 is, and whether they were fighting him. Vegeta tells Trunks that they are fighting the androids he told them about, but Trunks seems confused. Piccolo asks if these are not the androids, and the others are confused as well. Meanwhile, Bulma, Yajirobe, and Trunks continue to approach the battleground. Yajirobe threatens to throw Trunks out the window if they get closer, but Bulma tells him that Vegeta is the father and he acquiesces.
As the discussion about the androids continues, Krillin suggests that the androids are different since history has changed. Android 20 decides to escape by hiding among the rocks. Just then Bulma and Yajirobe arrive, and Android 20 yells out that Androids 17 and 18 will come for them soon, then hits Bulma's airplane with a Photon Wave. The airplane explodes, and Android 20 is gone when the smoke clears. Future Trunks manages to save Bulma and his younger self, and Vegeta decides to go after Android 20. However, Future Trunks gets in front of Vegeta and asks him why he did not try to save Bulma and his son. Vegeta says that he has no use for sentiment, and flies away. Bulma says that she believes Android 20 is actually Dr. Gero, having seen his picture in an academic journal, and wonders if he modified his own body.
- Future Trunks
- Android 20
- Tien Shinhan
- Android 19 (head)