Outlaw Star follows the outlaw Gene Starwind and his eleven year-old business associate, Jim Hawking. Together they run a small jack-of-all-trades business on the backwater planet Sentinel III. After the two take a job as bodyguards for a mysterious outlaw, they find themselves the owners of the XGP15A-II, a highly advanced prototype spacecraft, and the caretakers of a bio-android named Melfina.