Against Future Supreme Kai's will, Future Trunks pursues Future Dabura and fights him:
Future Trunks Future Gohan opening Another Road.jpg
Future Trunks (kid) and Future Gohan in the opening
If he defeats Future Dabura, after being wounded by Future Dabura while protecting a city from one of his Ki Blasts, Future Trunks realizes that he can not do it alone and the story progresses to chapter 2.
If he fails to defeat Future Dabura, one of Future Dabura's Ki Blasts mortally wounds Future Kibito when the latter takes the terrible blast with his own body to protect Future Trunks.
Though Future Kibito saved him from one blast, another comes shortly thereafter and hits Future Trunks. With no means of healing him, they have to resort to medical treatment. Meanwhile, with no one to oppose them, Future Babidi and Future Dabura gather enough energy to resurrected Future Majin Buu, who kills Future Dabura in short order and soon, where at first he was heeded by Buu, Future Babidi himself is killed as well. With no orders, Future Buu simply goes on destroying, purely for innocent fun. Though injured, Future Trunks is the only one who can face Future Majin Buu.
Future Buu kills him in a battle. With the death of Future Trunks, the fate of the world is sealed: Future Buu destroys the world, and then the universe, then he turns to the Kais. Those who could have stopped Buu were long gone, the world will soon return to nothingness.
