The story focuses on the Gatchaman, a group of superheroes, who protect earth. The series also focuses on the question on what it means to be a hero.

Early summer of 2015 in the city of Tachikawa, Japan. A "second metropolis" of Tokyo, Tachikawa is protected by the Gatchaman, warriors who fight in special reinforced suits called NOTE powered by the manifestation of their spiritual powers. After the introduction of their newest member, the energetic and cheerful Hajime Ichinose, the Gatchaman must deal with Berg Katze, an enigmatic alien creature who, having destroyed several planets, has turned his attention to Earth.