Adventure Mode is an exclusive story in Dragon Ball Z: Extreme Butōden, which acts as a sequel to Dragon Ball GT; as such the events of the Gods of the Universe Saga and Dragon Ball Super have not occurred, and this story acts as the GT equivalent of Battle of Gods.
Plot
Prologue
The Shadow Dragons return after they had been defeated years ago thanks to the Dragon Balls still existing and thus still possessing negative energy. They immediately turn into Omega Shenron who begins gathering minus energy, and warps time and space - mixing the past and the future together. Supreme Kai and Kibito (Kibito Kai has split at some point after GT), calls Goku to the Sacred World of the Kai and explains this to him, knowing that all of his opponents will re-appear from the past, Goku is anxious to fight Frieza, and says he will recruit Gohan and Vegeta to help. Supreme Kai says that they should work to gather the Ultimate Dragon Balls to seal the minus energy inside them and Goku agrees.
Chi-Chi does not want Goku to have Gohan get involved, as he has become a great scholar who supports his family, but Goku insists that this is for the fate of the galaxy, even so she does not want Gohan to help as their is no paycheck - but Gohan points out that if there is no galaxy, there will be no one left to pay them. Chi-Chi allows Gohan to go help, but only if Goku gets a job once this is over. Goku wants to test Gohan to see if he has slacked, but Gohan states that Pan has been training everyday, and so Gohan has as well. Goku defeats Gohan, who notes that he cannot match him, while Goku notes Gohan has gotten better.
In order to avoid being sensed by the villains, Goku suppresses his ki and uses the Nimbus to fly. Goku heads to Capsule Corp to pick up the Dragon Radar from Bulma. Goku explains the situation to Vegeta, who had noticed something was amiss. Vegeta wishes to fight Goku, and Goku defeats him in the match, with Goku and Vegeta noticing that each other have gotten stronger. Bulma is having trouble finding the Dragon Radar, so she suggests Goku go and meet Krillin and Yamcha in Parsley City. Goku meets them and explains the situation to them as well, Roshi is also present and notes that the peace has lasted longer than usual up until this point. He is happy with how his students turned out and tells them to spar, so they do. Goku suggest they all train at Kai's place but they all decline for different reasons.
Goku finds Vegeta and Trunks training, Trunks notes that he has not done any training since the search for the Black Dragon Balls but that he'll help. Trunks says he'll help protect Capsule Corp, but Vegeta notes that he is so weak that he wouldn't be able to beat Frieza (from the Battle of Namek) or Cell (from the Cell Games) and commands him to train harder. Super Saiyan Trunks trains a bit with Goku and defeats him with just one tenth of his base form's power, which is enough for Trunks to exclaim that Goku is on a whole other level. Vegeta commands Trunks to go and fight Frieza or Cell, but Trunks says it would be impossible for him to beat them.
Goku meets Roshi, who asks if Goku could gather the Dragon Balls in his spare time so Roshi can use them to wish for youth. Goku agrees to this.
Timeline placement
The events of the Adventure Mode occur several years after GT, at a point where Goku has regrown from a child to an adult.