Other source:
Without Babidi to control him, Majin Buu goes on a spree of destruction. Trunks returns to the lookout with the Dragon Radar. Baba shows up to tell Goku that he only has thirty minutes left. His transformation into Super Saiyan 3 was very draining, and it ate up a lot of his time that was left. Even though he is exhausted, he begins teaching Goten and Trunks the Fusion Dance. On the world of the Kais, Gohan begins training with even more intensity than before, determined to save the universe from Majin Buu.
