"Return to the Room of Spirit and Time" (トランクスと悟天精神と時の部屋に入る Torankusu to Goten Seishin to Toki no Heya ni Hairu, lit. "Trunks and Goten Enter the Room of Spirit and Time") is the two hundred ninety fourth chapter of Dragon Ball Z and the four hundred eighty-eighth overall chapter of the Dragon Ball manga.
On Sacred World of the Kai, Goku and Supreme Kai are trying to understand the surge of power they are feeling. Gohan is losing his temper and demands that Old Kai finish with the spell already. The old coot is not letting himself be rushed, and Gohan explodes, powering up and yelling that he wants to fight Super Buu. However, his body has undergone a transformation, and he wonders where this power has come from. The old coot needs more time to finish the spell, so Gohan sits down and meekly apologizes. The old coot returns to reading his manga. Goku asks Kaioshin if Old Kai has really given the boy this power, and Kaioshin is not so sure. Goku wonders how Gohan pulled this off.
On The Lookout, Goten and Trunks stare at the Super Buu, asking if this is really it. Piccolo confirms it, and then tries to get the boys to train in the Hyperbolic Time Chamber for the equivalent of 6 hours. Chi-Chi takes this chance to go up to Buu, still thinking that Buu killed him, very foolishly slaps him in the face and demands that he return her Gohan. Buu turns Chi-Chi into an egg and steps on her. Goten almost goes berserk, but Piccolo manages to get the boy to train in the Room of Spirit and Time rather than throw his life away needlessly right now, because they will use the Dragon Balls to revive Chi-Chi later. Trunks is sure that they can completely defeat Buu, and Goten is lost in hatred. Goten and Trunks are in the Room of Spirit and Time, and Trunks wants to eat but Goten keeps training, so Trunks runs to join his friend and keep up in power levels.
On the lookout, Videl asks Piccolo how Buu could know about her father, and Piccolo replies that Buu and Satan had become friends. Videl ponders this, as Buu gets tired of staring at the sand dial. He destroys the clock, and Piccolo asks for just 30 minutes more. But Buu blows a hole in the floor of the lookout, in front of the Piccolo's feet, and demands to be allowed to do some fighting. Piccolo relents, and leads the monster to the center of the palace. Krillin is afraid that Buu will be guided to the Room of Spirit and Time, and Piccolo just looks stonely resolute.