Dragon Ball Z Episode 78: Fighting Power: One Million??
Episode 78 of 291 of Dragon Ball Z, aired February 13, 1991, 25 minutes. Available with English subtitles and dub where released.
Episode summary
Because of a broken heart caused by Frieza's cruelty towards his people, Guru is gone, as well as Porunga and Vegeta's wish. Frieza arrives, furious being denied his wish. As the fight for the Universe has just begun, Piccolo finds Nail, and the wounded warrior makes an unexpected proposal.