Buu is Overwhelmed! Ultimate Gohan's Super Power!!
Gohan steps onto the battlefield to face Majin Buu, displaying the dramatic results of his completed ritual. As the long-awaited confrontation begins, Buu quickly finds himself pushed to his limits by this unexpected threat. Refusing to accept defeat, the monster resorts to a drastic, explosive strategy to reset the board and buy time for a new plan.
Aired 15/02/2015EP 44 - Buu is Overwhelmed! Ultimate Gohan's Super Power!!
Dragon Ball Z Kai: The Final Chapters
Since Cell's defeat Gohan has grown up and go to the university then she meets Videl which who has some adventures, then both and his new brother Goten are training for the new tournament, in which Goku came back from the dead for one day. In half of the tournament a misterious persons advice the group about the resurrection of the dangerous Majin Boo, but all plans fails and every one try new ways to stop The dangerous Majin Boo who gets stronger each time. Goku and his friends make everything for stopping them through fights.
(Source: Anime News Network, edited)
Note: Remastered version of the Majin Boo arc that adheres more to the manga's story.