Super Dragon Ball Heroes: Universe Mission!!

Having defeated Boo, Goku is starting to get bored with his life on Earth. His wife, Chi-chi, wants him to get a job, but all he wants to do is train and fight stronger enemies. Elsewhere in the universe, the God of Destruction, Beerus, and his attendant Whis are traveling from planet to planet in search of food and entertainment. After blowing up some hapless victims, Beerus is reminded of a man from his dreams with the moniker “Super Saiyan God,” or something like that… The God of Destruction sets his sights on Earth to track down this mysterious man! Maybe this will give Goku something to do? *Source: Viz Media, Vol. 1*

The story follows Future Trunks soon after the defeat of Cell in his own timeline, becoming a Time Patroller and assisting Chronoa in confronting the Time Breakers, later known as the Dark Empire Forces from the Demon Realm. The Dark Empire having revived their leader, Mechikabura, plan to retrieve artifacts known as the Dark Dragon Balls which have scattered across time and space, in order to restore him back into the prime of his youth. However the Dark Dragon Balls have merged with past villains, giving them new found might. Now it is up to Future Trunks, along with new allies such as Goku and Vegeta from stopping their plans from coming to fruition. (Source: Dragon Ball Wiki)

The Prison Planet was only the beginning of Fu's experiments... Based on the experimental data collected at the Prison Planet, Fu finally begins his real experiment! What is Fu's real goal, and what is his real power? Goku and companions from "Dark Demon Realm Mission" and "Universe Mission" appear! An experiment involving the whole universe and space-time!