There Is Planet Earth, Father! Frieza and King Cold Strike Back (That's Earth, Papa... Freeza and His Father Strike Back) is the fifty-fifth episode of Dragon Ball Z Kai. The episode first aired in Japan on May 2, 2010. Its American air date was February 17, 2011. Its Dragon Ball Z counterparts are "Frieza's Counterattack" and "The Mysterious Youth".
Summary
It has been a year since Goku defeated Frieza. Chi-Chi gets a private tutor for Gohan named Mr. Shu. Mr. Shu is a nasty man who throws out difficult questions, then whips Gohan if he doesn’t solve them. He attributes Gohan’s resistance to Goku, who won’t return. Chi-Chi is angry when she hears this, and chases Mr. Shu out. Vegeta returns from space, but is displeased that Goku isn’t there. Bulma suggests that he stay at her house until Goku returns. As he’s studying, Gohan senses a violent ki. That ki’s identity is… Frieza?! Gohan rushes to where Frieza and the other ki are. The other warriors have gathered, but Goku is nowhere to be seen. Frieza appears with his father King Cold. Frieza was left on the brink of death after his battle with Goku, and once King Cold’s spaceship saved him as he drifted through space, he was revived by becoming a cyborg. Frieza orders his underlings to kill all the Earthlings until Goku’s arrival. But a boy mysteriously appears and instantly cuts down Frieza’s underlings.