Set in an A.U where either Cooler or Frieza has taken over the universe due to the nonexistence of the Z- fighters, Earth is a dying planet due to centuries of drought and rampant disease, all of which had left it nothing more than a barren, rocky surface with little life to show. The few humans that have survived these dangers have managed to take shelter underground and rarely venture to the surface for reasons other than hunting what little life is left for subsidence. Of course, there is always the exception in groups of those ruled by fear, a human named Maren (Or Mira, if you prefer female) being rather brave and stupidly naive and not believing there is any true danger on the surface, routinely slipping away to hunt on his/her own rather than the customary group.
Being disconnected from the concept of a 'wide universe', Maren is thus unaware that there is a lucrative market among bounty hunters for 'rare species', humans being among the desired quarry of 'pet' among the elite that simply sees having one as a status symbol. A live human being able to fetch an incredibly high price, Maren has little chance of defending himself when a group of rogue bounty hunters manages to successfully capture him on one of his solo hunting adventures, the rest of Earth being destroyed in the process for the sake of a bit more money on Maren's head.
Eventually being sold off to Cooler/Frieza, the rebellious Maren isn't exactly willing to just sit back and be an outspoken punching bag by any means, using any chance he can to hone what little fighting technique he has in the hopes of an eventual escape. Of course, though, Cooler/ Frieza isn't the type to exactly 'own' pets just for show though, seeing a much greater use in using Maren for the entertaining destruction of various planets and other minor tasks than just having him be an ongoing pest.
Being rather gullible and not being in the best state for thinking situations out too clearly, Maren is given the 'deal' of taking part in the willing destruction of unneeded planets in exchange for training and the potential to someday have his old home restored with the power of the mysterious 'Dragon Balls'. Maren knowing little about the Dragon Balls and what they are capable of, he willingly accepts the deal but soon realizes he has gotten himself into a situation more dangerous than he ever thought he would be entwined in.