One day, a huge UFO spins over Japan and crashes into a rural farmland outside Nagaoka, disrupting Tsubasa Misudachi's ordinary life. As the Gatchaman, the legendary defenders of Tachikawa City, supervise the ordeal, a peaceful alien creature emerges from the spacecraft. In the ensuing chaos, Tsubasa is given a special high-tech notebook, or NOTE, from Gatchaman founder J.J. Robinson, signaling Tsubasa's sudden recruitment into their group. Under the tutelage of fellow hero Hajime Ichinose, Tsubasa slowly begins to adjust to life as a defender of justice.