The first Getter Robo series was published chronologically 15 years before the rest of the manga. Getter Robo pioneered the concept of combining and transforming robots. Millions of years ago, the sudden arrival of "Getter Rays" on Earth drove the dinosaurs deep underground. After evolving into sentient beings, they grew bitter and vengeful toward the humans who replaced them on the surface and began plotting an attack on humanity. Opposing them is Getter Robo, a machine built by Professor Saotome that uses the mysterious Getter Rays as its power source. It is piloted by three strong-willed young men: the violent martial artist Nagare Ryoma, the psychopathic yet highly intelligent revolutionary Jin Hayato, and the hot-blooded judo master Tomoe Musashi. Each controls one of three specially designed combat jets, which can be combined in different configurations to form three distinct types of giant robots: the flying, axe-wielding Getter-1; the quick, drill-wielding Getter-2; and the tough, tank-like Getter-3.