Hyuga Hyoko, a researcher in cosmic genetics, suffers an accident while studying unique cells found within a meteorite that collided with Earth, falling into a state of unconsciousness. However, her body reacts to the nutrient solution, granting her a steel-like physique and incredible strength, though she loses her memories in the process. Taking advantage of this transformation, the Japanese government decides to utilize her as a national defense asset. Operating as "Miss Sunrise," she becomes an elite combatant fighting against international threats. Yet her existence comes to the attention of the U.S. government, which begins exerting pressure to seize her body for experimental purposes.